There's not a lot of difference between the onChange and onBlur commands, but they both have their uses.
The onBlur event is triggered when the focus leaves the field which normally means that the user has pressed the tab key to move to the next field or used the mouse to click on another field. The onChange event does almost the same thing.
The difference is that if the data did not change, onBlur would still be called anyway but onChange would not. The first time the user enters this field the difference is moot. But if the cursor passes through the field again without the user changing the data then the event will be triggered again and an unnecessary call will be made to the server. So the most efficient event to use would be onChange. We need to create a function that will handle the onChange event and we need to call that function when the event occurs.
Here is some list of Event Handlers of Javascript:
* onAbort - The user aborts the loading of an image
* onBlur - form element loses focus or when a window or frame loses focus.
* onChange - select, text, or textarea field loses focus and its value has been modified.
* onClick - object on a form is clicked.
* onDblClick - user double-clicks a form element or a link.
* onDragDrop - user drops an object (e.g. file) onto the browser window.
* onError - loading of a document or image causes an error.
* onFocus - window, frame, frameset or form element receives focus.
* onKeyDown - user depresses a key.
* onKeyPress - user presses or holds down a key.
* onKeyUp - user releases a key.
* onLoad - browser finishes loading a window or all of the frames within a frameset.
* onMouseDown - user depresses a mouse button.
* onMouseMove - user moves the cursor.
* onMouseOut - cursor leaves an area or link.
* onMouseOver - cursor moves over an object or area.
* onMouseUp - user releases a mouse button.
* onMove - user or script moves a window or frame.
* onReset - user resets a form.
* onResize - user or script resizes a window or frame.
* onSelect - user selects some of the text within a text or textarea field.
* onSubmit - user submits a form.
* onUnload - user exits a document.
Friday, May 9, 2008
Thursday, May 8, 2008
The Difference between null and undefined
JavaScript is different from other programming languages by containin both undefined and null values, which may cause confusion.
null is a special value meaning "no value". null is a special object because typeof null returns 'object'.
On the other hand, undefined means that the variable has not been declared, or has not been given a value.
Following snippets display 'undefined':
Although null and undefined are slightly different, the == (equality) operator considers them equal, but the === (identity) operator doesn't.
null is a special value meaning "no value". null is a special object because typeof null returns 'object'.
On the other hand, undefined means that the variable has not been declared, or has not been given a value.
Following snippets display 'undefined':
// i is not declared anywhere in code
alert(typeof i);
alert(typeof i);
var i;
alert(typeof i);
alert(typeof i);
Although null and undefined are slightly different, the == (equality) operator considers them equal, but the === (identity) operator doesn't.
JavaScript substring vs. substr
The Difference Between JavaScript String Extraction Functions
When you write JavaScript, you need to know what string manipulation methods/functions are available.
JavaScript substring() Method
JavaScript substring is used to take a part of a string. The syntax of JavaScript substring method is given below:
* start-index: (Required - Numeric Value) - where to start the extraction
* stop-index: (Optional - Numeric Value) - where to stop the extraction
Notes about Javascript substring
* If start-index is equal to stop-index, JavaScript substring returns an empty string.
* If stop-index parameter is omitted, JavaScript substring extracts characters from start-index to the end of the string.
* If parameters are 0or NaN, the parameters are threated as 0.
* If parameters are greater than the string's length, the parameters qill use string's length.
* If start-index > stop-index, then the JavaScript substring function swaps 2 parameters.
substring Example:
The output of the above code is:
JavaScript substr() Method
The JavaScript substr() method works slightly different. Instead of the second parameter being an index number, it gives the number of characters. The syntax of JavaScript substr() is given below:
* start-index: (Required - Numeric Value) - where to start the extraction
* length: (Optional - Numeric Value) - how many characters to extract
Notes about substr:
* To extract characters from the end of the string, use a negative start-index. (Internet Explorer returns the whole string which is wrong.)
* If the length parameter is omitted, JavaScript substr method extracts to the end of the string.
* substr() is not supported by Netscape 2, Netscape 3, Internet Explorer 3 and Opera 3.
* substr() is not cross-browser.
JavaScript substr Example
The output of the above code is:
When you write JavaScript, you need to know what string manipulation methods/functions are available.
JavaScript substring() Method
JavaScript substring is used to take a part of a string. The syntax of JavaScript substring method is given below:
stringObjectToTakeAPartOf.substring(start-index,stop-index)
* start-index: (Required - Numeric Value) - where to start the extraction
* stop-index: (Optional - Numeric Value) - where to stop the extraction
Notes about Javascript substring
* If start-index is equal to stop-index, JavaScript substring returns an empty string.
* If stop-index parameter is omitted, JavaScript substring extracts characters from start-index to the end of the string.
* If parameters are 0or NaN, the parameters are threated as 0.
* If parameters are greater than the string's length, the parameters qill use string's length.
* If start-index > stop-index, then the JavaScript substring function swaps 2 parameters.
substring Example:
<script type="text/javascript">
var str = "Hello World";
document.write(str.substring(4,8));
</script>
var str = "Hello World";
document.write(str.substring(4,8));
</script>
The output of the above code is:
o wo
JavaScript substr() Method
The JavaScript substr() method works slightly different. Instead of the second parameter being an index number, it gives the number of characters. The syntax of JavaScript substr() is given below:
stringObjectToTakeAPartOf.substr(start-index,length)
* start-index: (Required - Numeric Value) - where to start the extraction
* length: (Optional - Numeric Value) - how many characters to extract
Notes about substr:
* To extract characters from the end of the string, use a negative start-index. (Internet Explorer returns the whole string which is wrong.)
* If the length parameter is omitted, JavaScript substr method extracts to the end of the string.
* substr() is not supported by Netscape 2, Netscape 3, Internet Explorer 3 and Opera 3.
* substr() is not cross-browser.
JavaScript substr Example
<script type="text/javascript">
var str = "Hello World";
document.write(str.substr(4,8));
</script>
var str = "Hello World";
document.write(str.substr(4,8));
</script>
The output of the above code is:
o wo
location.href vs. location.replace - The Difference Between JavaScript Url Redirection Methods
JavaScript offers several ways to display a different page in the current browser window.
Redirecting visitors with Javascript is straightforward. The simplest way is to use one of the methods given below.
location.href Method
Including the following script will immediately redirect visitors to the URL entered.
location.replace Method
Including the following script will immediately redirect visitors to the URL entered.
The difference between location.href and location.replace
The difference between location.href and location.replace is that location.replace creates a new history entry on the visitor's browser meaning that if they hit the back button, they can get in a 'redirection loop' which is usually undesirable and may have unwanted side effects.
Redirecting visitors with Javascript is straightforward. The simplest way is to use one of the methods given below.
location.href Method
Including the following script will immediately redirect visitors to the URL entered.
<script type="text/javascript">
location.href='http://it-aspnet.blogspot.com';
</script>
location.href='http://it-aspnet.blogspot.com';
</script>
location.replace Method
Including the following script will immediately redirect visitors to the URL entered.
<script type="text/javascript">
location.replace('http://it-aspnet.blogspot.com/');
</script>
location.replace('http://it-aspnet.blogspot.com/');
</script>
The difference between location.href and location.replace
The difference between location.href and location.replace is that location.replace creates a new history entry on the visitor's browser meaning that if they hit the back button, they can get in a 'redirection loop' which is usually undesirable and may have unwanted side effects.
Differences Between Convert, Parse and TryParse Methods
.Net provides several different ways to extract integers from strings. In this article, I will present the differences between Parse, TryParse and ConvertTo.
Parse
This function takes a string and tries to extract an integer from it and returns the integer. If the string is not a numerical value, the method throws FormatException. If the extracted number is too big, it throws OverflowException. Finally, if the string value is null, it throws ArgumentNullException.
Convert
This function checks for a null value and if the value is null, it returns 0 instead of throwing an exception. If the string is not a numerical value, the method throws FormatException. If the extracted number is too big, it throws OverflowException.
TryParse
This function is new in .Net 2.0. Since exception handling is very slow, TryParse function returns a boolean indicating if it was able to successfully parse a number instead of throwing an exception. Therefore, you have to pass into TryParse both the string to be parsed and an out parameter to fill in. Using the TryParse static method, you can avoid the exception and ambiguous result when the string is null.
Examples
Parse
This function takes a string and tries to extract an integer from it and returns the integer. If the string is not a numerical value, the method throws FormatException. If the extracted number is too big, it throws OverflowException. Finally, if the string value is null, it throws ArgumentNullException.
Int32 intValue = Int32.Parse(str);
Convert
This function checks for a null value and if the value is null, it returns 0 instead of throwing an exception. If the string is not a numerical value, the method throws FormatException. If the extracted number is too big, it throws OverflowException.
Int32 intValue = Convert.ToInt32(str);
TryParse
This function is new in .Net 2.0. Since exception handling is very slow, TryParse function returns a boolean indicating if it was able to successfully parse a number instead of throwing an exception. Therefore, you have to pass into TryParse both the string to be parsed and an out parameter to fill in. Using the TryParse static method, you can avoid the exception and ambiguous result when the string is null.
bool isParsed = Int32.TryParse(str, out intValue);
Examples
string str1 = "1234";
string str2 = "1234.65";
string str3 = null;
string str4 = "999999999999999999999999999999999999999999";
int intValue;
bool isParsed;
intValue= Int32.Parse(str1); //1234
intValue= Int32.Parse(str2); //throws FormatException
intValue= Int32.Parse(str3); //throws ArgumentNullException
intValue= Int32.Parse(str4); //throws OverflowException
intValue= Convert.ToInt32(str1); //1234
intValue= Convert.ToInt32(str2); //throws FormatException
intValue= Convert.ToInt32(str3); //0
intValue= Convert.ToInt32(str4); //throws OverflowException
isParsed= Int32.TryParse(str1, out intValue); //isParsed=true 1234
isParsed= Int32.TryParse(str2, out intValue); //isParsed=false 0
isParsed= Int32.TryParse(str3, out intValue); //isParsed=false 0
isParsed= Int32.TryParse(str4, out intValue); //isParsed=false 0
string str2 = "1234.65";
string str3 = null;
string str4 = "999999999999999999999999999999999999999999";
int intValue;
bool isParsed;
intValue= Int32.Parse(str1); //1234
intValue= Int32.Parse(str2); //throws FormatException
intValue= Int32.Parse(str3); //throws ArgumentNullException
intValue= Int32.Parse(str4); //throws OverflowException
intValue= Convert.ToInt32(str1); //1234
intValue= Convert.ToInt32(str2); //throws FormatException
intValue= Convert.ToInt32(str3); //0
intValue= Convert.ToInt32(str4); //throws OverflowException
isParsed= Int32.TryParse(str1, out intValue); //isParsed=true 1234
isParsed= Int32.TryParse(str2, out intValue); //isParsed=false 0
isParsed= Int32.TryParse(str3, out intValue); //isParsed=false 0
isParsed= Int32.TryParse(str4, out intValue); //isParsed=false 0
Wednesday, May 7, 2008
What is the difference between HTML and XHTML?
If you’ve mastered HTML, you’re 90% of the way towards using XHTML. They’re actually very much the same thing—tag-based markup languages used to display web pages. The difference is only seen by the people creating the pages (web designers, programmers, etc.) and focuses on "forgivability"— HTML allows for some ugly code (mixed-case tags like <BoDy>, improperly nested elements, and unclosed tags), while XHTML does not. If you write HTML, it’s probably a good idea to start using XHTML practices anyway. It will take 5 minutes to learn, and it’s just a better way of doing things.
In XHTML, all tags must be lowercase
This is simple enough. Instead of using tags like <P>, <STRONG>, and <TABLE>, use <p>, <strong>, and <table>. Look at that! You’re 1/3rd of the way towards being an XHTML guru.
In XHTML, all tags must be closed
Again, something a good Web designer does anyway. But if you’re one the few people who still leaves <p> tags unclosed, now’s the time to start closing them.
Example of valid HTML:
Equivalent in XHTML:
Tags that don’t contain data (like breaks, images, and horizontal rules) should also be closed in HTML. There’s no need to write an opening and closing tag, though. We can use the perfectly acceptable shortcut:
In XHTML, tags must be properly nested
Here’s another area where good HTML coders are properly writing valid XHTML, even if they’re not aware. In HTML, the following code might display exactly as you intended:
Although this might work, it’s not “good” code. And for the purposes of this article, not valid XHTML either. To complete your XHTML training, simply make sure your tags are properly nested:
XHTML wrapup
XHTML is just cleaner HTML—tags are consistently lowercase, all tags are closed, and tags are properly nested. Making your pages valid XHTML is a piece of cake.
In XHTML, all tags must be lowercase
This is simple enough. Instead of using tags like <P>, <STRONG>, and <TABLE>, use <p>, <strong>, and <table>. Look at that! You’re 1/3rd of the way towards being an XHTML guru.
In XHTML, all tags must be closed
Again, something a good Web designer does anyway. But if you’re one the few people who still leaves <p> tags unclosed, now’s the time to start closing them.
Example of valid HTML:
<p>This is a paragraph
Equivalent in XHTML:
<p>This is a paragraph</p>
Tags that don’t contain data (like breaks, images, and horizontal rules) should also be closed in HTML. There’s no need to write an opening and closing tag, though. We can use the perfectly acceptable shortcut:
<!— Examples of properly closed XHTML tags -->
<!—Properly closed image -->
<img src="someimage.gif" alt="An image" />
<!—Properly closed break tag -->
<br />
<!—Properly closed horizontal rule -->
<hr />
<!—Properly closed image -->
<img src="someimage.gif" alt="An image" />
<!—Properly closed break tag -->
<br />
<!—Properly closed horizontal rule -->
<hr />
In XHTML, tags must be properly nested
Here’s another area where good HTML coders are properly writing valid XHTML, even if they’re not aware. In HTML, the following code might display exactly as you intended:
<strong>
<em>
Here’s some bold and italicized text
</strong>
</em>
<em>
Here’s some bold and italicized text
</strong>
</em>
Although this might work, it’s not “good” code. And for the purposes of this article, not valid XHTML either. To complete your XHTML training, simply make sure your tags are properly nested:
<strong>
<em>
Here’s a valid XHTML version of bold italicized code
</em>
</strong>
<em>
Here’s a valid XHTML version of bold italicized code
</em>
</strong>
XHTML wrapup
XHTML is just cleaner HTML—tags are consistently lowercase, all tags are closed, and tags are properly nested. Making your pages valid XHTML is a piece of cake.
What is the difference between <span> and <div> tags?
<span> and <div> tags both allow a web designer to style text and add other formatting attributes to their web page. They are not interchangeable tags, though. <div> tags are block-level elements, whereas <span> tags are not.
Both <span> and <div> tags allow you to apply CSS styles
<span> and <div> tags are both fine for applying inline CSS formatting. Consider the following code:
The output of this code is the same as:
<div> tags are block elements that allow you to position elements contained within them
<div> tags are block elements. This means they can "hold" other HTML elements, and they can be positioned anywhere on the screen. For this reason, <div> tags can be used for replacing table-based web designs.
<span> tags are NOT block elements
Unlike <div> tags, <span> tags cannot hold other HTML tags. They should only be used for inline styling of text. Consider the following code:
This code will probably render OK in most browsers, but it is actually incorrect. Remember, since the <span> tag is not a block-level element, it cannot contain other HTML tags. The correct way to write this code would be:
While this code is correct, it can be written more efficiently by removing the <span> tag altogether:
<div> tags create line breaks, <span> tags do not
Since <div> tags are block elements, they create line breaks. This is the same effect as a <p> tag. <span> tags do not create line breaks, which makes them perfect for styling text in the middle of a sentence. Here’s an example of a <span> tag used to style text in the middle of a sentence. The same code using <div> instead of <span> would produce undesired results.
<p>It's snowing in the Northeast today. Some towns received as much as <span style="font-style:italic;font-weight:bold;">6 inches</span> of snow.</p>
Summary of <span> vs. <div> tags
<span> tags are useful if you need to apply specific formatting styles to text in the middle of a sentence, or in one place on your Web page. They are far less powerful than <div> tags, though, as a <div> will allow you to create blocks of content (like table-based Web designs) and position elements on the screen.
Both <span> and <div> tags allow you to apply CSS styles
<span> and <div> tags are both fine for applying inline CSS formatting. Consider the following code:
<div style="color:#000000;
font-weight:bold;
font-size:14px">
Here’s some text in between div tags</div>
font-weight:bold;
font-size:14px">
Here’s some text in between div tags</div>
The output of this code is the same as:
<span style="color:#000000;
font-weight:bold;
font-size:14px">
Here’s some text in between span tags</span>
font-weight:bold;
font-size:14px">
Here’s some text in between span tags</span>
<div> tags are block elements that allow you to position elements contained within them
<div> tags are block elements. This means they can "hold" other HTML elements, and they can be positioned anywhere on the screen. For this reason, <div> tags can be used for replacing table-based web designs.
<span> tags are NOT block elements
Unlike <div> tags, <span> tags cannot hold other HTML tags. They should only be used for inline styling of text. Consider the following code:
<span>
<p>This is some text sized at 14 pixels.</p>
</span>
<p>This is some text sized at 14 pixels.</p>
</span>
This code will probably render OK in most browsers, but it is actually incorrect. Remember, since the <span> tag is not a block-level element, it cannot contain other HTML tags. The correct way to write this code would be:
<p><span>
This is some text sized at 14 pixels.
</span></p>
This is some text sized at 14 pixels.
</span></p>
While this code is correct, it can be written more efficiently by removing the <span> tag altogether:
<p style="font-size:14px">
This is some text sized at 14 pixels.
</p>
This is some text sized at 14 pixels.
</p>
<div> tags create line breaks, <span> tags do not
Since <div> tags are block elements, they create line breaks. This is the same effect as a <p> tag. <span> tags do not create line breaks, which makes them perfect for styling text in the middle of a sentence. Here’s an example of a <span> tag used to style text in the middle of a sentence. The same code using <div> instead of <span> would produce undesired results.
<p>It's snowing in the Northeast today. Some towns received as much as <span style="font-style:italic;font-weight:bold;">6 inches</span> of snow.</p>
Summary of <span> vs. <div> tags
<span> tags are useful if you need to apply specific formatting styles to text in the middle of a sentence, or in one place on your Web page. They are far less powerful than <div> tags, though, as a <div> will allow you to create blocks of content (like table-based Web designs) and position elements on the screen.
Monday, May 5, 2008
ASP.NET - Web Pages
A simple ASP.NET page looks just like an ordinary HTML page.
Hello World
To start learning ASP.NET, we will construct a very simple HTML page that will display "Hello World!" in an Internet browser like this:
Hello World in HTML
This code displays the example as an HTML page:
If you want to try it yourself, save the code in a file called firstpage.html, and create a link to the file.
Hello World in ASP.NET
The simplest way to convert an HTML page into an ASP.NET page is to copy the HTML file to a new file with an .aspx extension.
This code displays our example as an ASP.NET page:
If you want to try it yourself, save the code in a file called firstpage.aspx, and create a link to the file.
How Does it Work?
Fundamentally an ASP.NET page is just the same as an HTML page.
An HTML page has the extension .htm. If a browser requests an HTML page from the server, the server sends the page to the browser without any modifications.
An ASP.NET page has the extension .aspx. If a browser requests an ASP.NET page, the server processes any executable code in the page, before the result is sent back to the browser.
The ASP.NET page above does not contain any executable code, so nothing is executed. In the next examples we will add some executable code to the page to demonstrate the difference between static HTML pages and dynamic ASP pages.
Classic ASP
Active Server Pages (ASP) has been around for several years. With ASP, executable code can be placed inside HTML pages.
Previous versions of ASP (before ASP .NET) are often called Classic ASP.
ASP.NET is not fully compatible with Classic ASP, but most Classic ASP pages will work fine as ASP.NET pages, with only minor changes.
Dynamic Page in Classic ASP
To demonstrate how ASP can display pages with dynamic content, we have added some executable code (in red) to the previous example:
The code inside the <% --%> tags is executed on the server.
Response.Write is ASP code for writing something to the HTML output stream.
Now() is a function returning the servers current date and time.
If you want to try it yourself, save the code in a file called dynpage.asp, and create a link to the file.
Dynamic Page in ASP .NET
This following code displays our example as an ASP.NET page:
If you want to try it yourself, save the code in a file called dynpage.aspx, and create a link to the file.
ASP.NET vs Classic ASP
The previous examples didn't demonstrate any differences between ASP.NET and Classic ASP.
As you can see from the two latest examples there are no differences between the two ASP and ASP.NET pages.
In the next chapters you will see how server controls make ASP.NET more powerful than Classic ASP.
Hello World
To start learning ASP.NET, we will construct a very simple HTML page that will display "Hello World!" in an Internet browser like this:
| Hello World! |
Hello World in HTML
This code displays the example as an HTML page:
<html> |
If you want to try it yourself, save the code in a file called firstpage.html, and create a link to the file.
Hello World in ASP.NET
The simplest way to convert an HTML page into an ASP.NET page is to copy the HTML file to a new file with an .aspx extension.
This code displays our example as an ASP.NET page:
<html> |
If you want to try it yourself, save the code in a file called firstpage.aspx, and create a link to the file.
How Does it Work?
Fundamentally an ASP.NET page is just the same as an HTML page.
An HTML page has the extension .htm. If a browser requests an HTML page from the server, the server sends the page to the browser without any modifications.
An ASP.NET page has the extension .aspx. If a browser requests an ASP.NET page, the server processes any executable code in the page, before the result is sent back to the browser.
The ASP.NET page above does not contain any executable code, so nothing is executed. In the next examples we will add some executable code to the page to demonstrate the difference between static HTML pages and dynamic ASP pages.
Classic ASP
Active Server Pages (ASP) has been around for several years. With ASP, executable code can be placed inside HTML pages.
Previous versions of ASP (before ASP .NET) are often called Classic ASP.
ASP.NET is not fully compatible with Classic ASP, but most Classic ASP pages will work fine as ASP.NET pages, with only minor changes.
Dynamic Page in Classic ASP
To demonstrate how ASP can display pages with dynamic content, we have added some executable code (in red) to the previous example:
<html> |
The code inside the <% --%> tags is executed on the server.
Response.Write is ASP code for writing something to the HTML output stream.
Now() is a function returning the servers current date and time.
If you want to try it yourself, save the code in a file called dynpage.asp, and create a link to the file.
Dynamic Page in ASP .NET
This following code displays our example as an ASP.NET page:
<html> |
If you want to try it yourself, save the code in a file called dynpage.aspx, and create a link to the file.
ASP.NET vs Classic ASP
The previous examples didn't demonstrate any differences between ASP.NET and Classic ASP.
As you can see from the two latest examples there are no differences between the two ASP and ASP.NET pages.
In the next chapters you will see how server controls make ASP.NET more powerful than Classic ASP.
Installing ASP.NET
ASP.NET is easy to install. Just follow the instructions below.
What You Need
A Windows Computer
ASP.NET is a Microsoft technology. To run ASP.NET you need a computer capable of running Windows.
Windows 2000 or XP
If you are serious about developing ASP.NET applications you should install Windows 2000 Professional or Windows XP Professional.
In both cases, make sure you install the Internet Information Services (IIS) from the Add/Remove Windows components dialog.
Service Packs and Updates
Before ASP.NET can be installed on your computer, it is necessary to have all relevant service packs and security updates installed.
The easiest way to do this is to activate your Windows Internet Update. When you access the Windows Update page, you will be instructed to install the latest service packs and all critical security updates. For Windows 2000, make sure you install Service Pack 2. I will also recommend that you install Internet Explorer 6.
Read the note about connection speed and download time at the bottom of this page.
Remove Your Beta Version
If you have a Beta version of ASP.NET installed, we recommend that you completely uninstall it. Or even better: start with a fresh Windows 2000 or XP installation.
Install .NET
From your Windows Update you can now select to install the Microsoft .NET Framework.
After download, the .NET framework will install itself on your computer - there are no options to select for installation.
You should now be ready to develop your first ASP.NET application!
The .NET Software Development Kit
If you have the necessary bandwidth to download over 130 MB, you might consider downloading the full Microsoft .NET Software Development Kit (SDK).
We fully recommend getting the SDK for learning more about .NET and for the documentation, samples, and tools included.
Connection Speed and Download Time
If you have a slow Internet connection, you might have problems downloading large files like the service packs, the SDK and the latest version of Internet Explorer.
If download speed is a problem, our best suggestion is to get the latest files from someone else, from a colleague, from a friend, or from one of the CDs that comes with many popular computer magazines. Look for Windows 2000 Service Pack 2, Internet Explorer 6, and the Microsoft .NET Framework.
What You Need
A Windows Computer
ASP.NET is a Microsoft technology. To run ASP.NET you need a computer capable of running Windows.
Windows 2000 or XP
If you are serious about developing ASP.NET applications you should install Windows 2000 Professional or Windows XP Professional.
In both cases, make sure you install the Internet Information Services (IIS) from the Add/Remove Windows components dialog.
Service Packs and Updates
Before ASP.NET can be installed on your computer, it is necessary to have all relevant service packs and security updates installed.
The easiest way to do this is to activate your Windows Internet Update. When you access the Windows Update page, you will be instructed to install the latest service packs and all critical security updates. For Windows 2000, make sure you install Service Pack 2. I will also recommend that you install Internet Explorer 6.
Read the note about connection speed and download time at the bottom of this page.
Remove Your Beta Version
If you have a Beta version of ASP.NET installed, we recommend that you completely uninstall it. Or even better: start with a fresh Windows 2000 or XP installation.
Install .NET
From your Windows Update you can now select to install the Microsoft .NET Framework.
After download, the .NET framework will install itself on your computer - there are no options to select for installation.
You should now be ready to develop your first ASP.NET application!
The .NET Software Development Kit
If you have the necessary bandwidth to download over 130 MB, you might consider downloading the full Microsoft .NET Software Development Kit (SDK).
We fully recommend getting the SDK for learning more about .NET and for the documentation, samples, and tools included.
Connection Speed and Download Time
If you have a slow Internet connection, you might have problems downloading large files like the service packs, the SDK and the latest version of Internet Explorer.
If download speed is a problem, our best suggestion is to get the latest files from someone else, from a colleague, from a friend, or from one of the CDs that comes with many popular computer magazines. Look for Windows 2000 Service Pack 2, Internet Explorer 6, and the Microsoft .NET Framework.
Differences Between ASP and ASP.NET
ASP.NET has better language support, a large set of new controls and XML based components, and better user authentication. ASP.NET provides increased performance by running compiled code. ASP.NET code is not fully backward compatible with ASP.
New in ASP.NET
* Better language support
* Programmable controls
* Event-driven programming
* XML-based components
* User authentication, with accounts and roles
* Higher scalability
* Increased performance - Compiled code
* Easier configuration and deployment
* Not fully ASP compatible
Language Support
ASP.NET uses the new ADO.NET.
ASP.NET supports full Visual Basic, not VBScript.
ASP.NET supports C# (C sharp) and C++.
ASP.NET supports JScript as before.
ASP.NET Controls
ASP.NET contains a large set of HTML controls. Almost all HTML elements on a page can be defined as ASP.NET control objects that can be controlled by scripts.
ASP.NET also contains a new set of object oriented input controls, like programmable list boxes and validation controls.
A new data grid control supports sorting, data paging, and everything you expect from a dataset control.
Event Aware Controls
All ASP.NET objects on a Web page can expose events that can be processed by ASP.NET code.
Load, Click and Change events handled by code makes coding much simpler and much better organized.
ASP.NET Components
ASP.NET components are heavily based on XML. Like the new AD Rotator, that uses XML to store advertisement information and configuration.
User Authentication
ASP.NET supports forms-based user authentication, including cookie management and automatic redirecting of unauthorized logins.
(You can still do your custom login page and custom user checking).
User Accounts and Roles
AS .NET allows for user accounts and roles, to give each user (with a given role) access to different server code and executables.
High Scalability
Much has been done with ASP.NET to provide greater scalability.
Server to server communication has been greatly enhanced, making it possible to scale an application over several servers. One example of this is the ability to run XML parsers, XSL transformations and even resource hungry session objects on other servers.
Compiled Code
The first request for an ASP.NET page on the server will compile the ASP.NET code and keep a cached copy in memory. The result of this is greatly increased performance.
Easy Configuration
Configuration of ASP.NET is done with plain text files.
Configuration files can be uploaded or changed while the application is running. No need to restart the server. No more metabase or registry puzzle.
Easy Deployment
No more server restart to deploy or replace compiled code. ASP.NET simply redirects all new requests to the new code.
Compatibility
ASP.NET is not fully compatible with earlier versions of ASP, so most of the old ASP code will need some changes to run under ASP.NET.
To overcome this problem, ASP.NET uses a new file extension ".aspx". This will make ASP.NET applications able to run side by side with standard ASP applications on the same server.
New in ASP.NET
* Better language support
* Programmable controls
* Event-driven programming
* XML-based components
* User authentication, with accounts and roles
* Higher scalability
* Increased performance - Compiled code
* Easier configuration and deployment
* Not fully ASP compatible
Language Support
ASP.NET uses the new ADO.NET.
ASP.NET supports full Visual Basic, not VBScript.
ASP.NET supports C# (C sharp) and C++.
ASP.NET supports JScript as before.
ASP.NET Controls
ASP.NET contains a large set of HTML controls. Almost all HTML elements on a page can be defined as ASP.NET control objects that can be controlled by scripts.
ASP.NET also contains a new set of object oriented input controls, like programmable list boxes and validation controls.
A new data grid control supports sorting, data paging, and everything you expect from a dataset control.
Event Aware Controls
All ASP.NET objects on a Web page can expose events that can be processed by ASP.NET code.
Load, Click and Change events handled by code makes coding much simpler and much better organized.
ASP.NET Components
ASP.NET components are heavily based on XML. Like the new AD Rotator, that uses XML to store advertisement information and configuration.
User Authentication
ASP.NET supports forms-based user authentication, including cookie management and automatic redirecting of unauthorized logins.
(You can still do your custom login page and custom user checking).
User Accounts and Roles
AS .NET allows for user accounts and roles, to give each user (with a given role) access to different server code and executables.
High Scalability
Much has been done with ASP.NET to provide greater scalability.
Server to server communication has been greatly enhanced, making it possible to scale an application over several servers. One example of this is the ability to run XML parsers, XSL transformations and even resource hungry session objects on other servers.
Compiled Code
The first request for an ASP.NET page on the server will compile the ASP.NET code and keep a cached copy in memory. The result of this is greatly increased performance.
Easy Configuration
Configuration of ASP.NET is done with plain text files.
Configuration files can be uploaded or changed while the application is running. No need to restart the server. No more metabase or registry puzzle.
Easy Deployment
No more server restart to deploy or replace compiled code. ASP.NET simply redirects all new requests to the new code.
Compatibility
ASP.NET is not fully compatible with earlier versions of ASP, so most of the old ASP code will need some changes to run under ASP.NET.
To overcome this problem, ASP.NET uses a new file extension ".aspx". This will make ASP.NET applications able to run side by side with standard ASP applications on the same server.
ASP.NET Introduction
ASP.NET is the latest version of Microsoft's Active Server Pages technology (ASP).
What You Should Already Know
Before you continue you should have a basic understanding of the following:
* WWW, HTML, XML and the basics of building Web pages
* Scripting languages like JavaScript or VBScript
* The basics of server side scripting like ASP or PHP
What is Classic ASP?
Microsoft's previous server side scripting technology ASP (Active Server Pages) is now often called classic ASP.
ASP 3.0 was the last version of the classic ASP.
ASP.NET is Not ASP
ASP.NET is the next generation ASP, but it's not an upgraded version of ASP.
ASP.NET is an entirely new technology for server-side scripting. It was written from the ground up and is not backward compatible with classic ASP.
ASP.NET is the major part of the Microsoft's .NET Framework.
What is ASP.NET?
ASP.NET is a server side scripting technology that enables scripts (embedded in web pages) to be executed by an Internet server.
* ASP.NET is a Microsoft Technology
* ASP stands for Active Server Pages
* ASP.NET is a program that runs inside IIS
* IIS (Internet Information Services) is Microsoft's Internet server
* IIS comes as a free component with Windows servers
* IIS is also a part of Windows 2000 and XP Professional
What is an ASP.NET File?
* An ASP.NET file is just the same as an HTML file
* An ASP.NET file can contain HTML, XML, and scripts
* Scripts in an ASP.NET file are executed on the server
* An ASP.NET file has the file extension ".aspx"
How Does ASP.NET Work?
* When a browser requests an HTML file, the server returns the file
* When a browser requests an ASP.NET file, IIS passes the request to the ASP.NET engine on the server
* The ASP.NET engine reads the file, line by line, and executes the scripts in the file
* Finally, the ASP.NET file is returned to the browser as plain HTML
What is ASP+?
ASP+ is the same as ASP.NET.
ASP+ is just an early name used by Microsoft when they developed ASP.NET.
The Microsoft .NET Framework
The .NET Framework is the infrastructure for the Microsoft .NET platform.
The .NET Framework is an environment for building, deploying, and running Web applications and Web Services.
Microsoft's first server technology ASP (Active Server Pages), was a powerful and flexible "programming language". But it was too code oriented. It was not an application framework and not an enterprise development tool.
The Microsoft .NET Framework was developed to solve this problem.
.NET Frameworks keywords:
* Easier and quicker programming
* Reduced amount of code
* Declarative programming model
* Richer server control hierarchy with events
* Larger class library
* Better support for development tools
The .NET Framework consists of 3 main parts:
Programming languages:
* C# (Pronounced C sharp)
* Visual Basic (VB .NET)
* J# (Pronounced J sharp)
Server technologies and client technologies:
* ASP .NET (Active Server Pages)
* Windows Forms (Windows desktop solutions)
* Compact Framework (PDA / Mobile solutions)
Development environments:
* Visual Studio .NET (VS .NET)
* Visual Web Developer
ASP.NET 2.0
ASP.NET 2.0 improves upon ASP.NET by adding support for several new features.
ASP.NET 3.0
ASP.NET 3.0 is not a new version of ASP.NET. It's just the name for a new ASP.NET 2.0 framework library with support for Windows Presentation Foundation, Windows Communication Foundation, Windows Workflow Foundation; and Windows CardSpace.
What You Should Already Know
Before you continue you should have a basic understanding of the following:
* WWW, HTML, XML and the basics of building Web pages
* Scripting languages like JavaScript or VBScript
* The basics of server side scripting like ASP or PHP
What is Classic ASP?
Microsoft's previous server side scripting technology ASP (Active Server Pages) is now often called classic ASP.
ASP 3.0 was the last version of the classic ASP.
ASP.NET is Not ASP
ASP.NET is the next generation ASP, but it's not an upgraded version of ASP.
ASP.NET is an entirely new technology for server-side scripting. It was written from the ground up and is not backward compatible with classic ASP.
ASP.NET is the major part of the Microsoft's .NET Framework.
What is ASP.NET?
ASP.NET is a server side scripting technology that enables scripts (embedded in web pages) to be executed by an Internet server.
* ASP.NET is a Microsoft Technology
* ASP stands for Active Server Pages
* ASP.NET is a program that runs inside IIS
* IIS (Internet Information Services) is Microsoft's Internet server
* IIS comes as a free component with Windows servers
* IIS is also a part of Windows 2000 and XP Professional
What is an ASP.NET File?
* An ASP.NET file is just the same as an HTML file
* An ASP.NET file can contain HTML, XML, and scripts
* Scripts in an ASP.NET file are executed on the server
* An ASP.NET file has the file extension ".aspx"
How Does ASP.NET Work?
* When a browser requests an HTML file, the server returns the file
* When a browser requests an ASP.NET file, IIS passes the request to the ASP.NET engine on the server
* The ASP.NET engine reads the file, line by line, and executes the scripts in the file
* Finally, the ASP.NET file is returned to the browser as plain HTML
What is ASP+?
ASP+ is the same as ASP.NET.
ASP+ is just an early name used by Microsoft when they developed ASP.NET.
The Microsoft .NET Framework
The .NET Framework is the infrastructure for the Microsoft .NET platform.
The .NET Framework is an environment for building, deploying, and running Web applications and Web Services.
Microsoft's first server technology ASP (Active Server Pages), was a powerful and flexible "programming language". But it was too code oriented. It was not an application framework and not an enterprise development tool.
The Microsoft .NET Framework was developed to solve this problem.
.NET Frameworks keywords:
* Easier and quicker programming
* Reduced amount of code
* Declarative programming model
* Richer server control hierarchy with events
* Larger class library
* Better support for development tools
The .NET Framework consists of 3 main parts:
Programming languages:
* C# (Pronounced C sharp)
* Visual Basic (VB .NET)
* J# (Pronounced J sharp)
Server technologies and client technologies:
* ASP .NET (Active Server Pages)
* Windows Forms (Windows desktop solutions)
* Compact Framework (PDA / Mobile solutions)
Development environments:
* Visual Studio .NET (VS .NET)
* Visual Web Developer
ASP.NET 2.0
ASP.NET 2.0 improves upon ASP.NET by adding support for several new features.
ASP.NET 3.0
ASP.NET 3.0 is not a new version of ASP.NET. It's just the name for a new ASP.NET 2.0 framework library with support for Windows Presentation Foundation, Windows Communication Foundation, Windows Workflow Foundation; and Windows CardSpace.
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