Active Server Pages
|
ASP has other meanings. See its disambiguation page.
Active Server Pages (ASP) is Microsoft's server-side technology for dynamically-generated web pages that is marketed as an add-on to Internet Information Services (IIS).
Programming ASP websites is made easier by various built-in objects. Each object corresponds to a group of frequently-used functionality useful for creating dynamic web pages. In ASP 3.0 there are six such built-in objects: Application, ASPError, Request, Response, Server and Session. Session, for example, is a cookie-based session object that maintains variables from page to page. Application Test Center is also available for load testing.
Most ASP pages are written in VBScript. Other scripting languages can be selected by using the @Language directive. JScript (Microsoft's implementation of JavaScript) is the other language that is usually available. PerlScript (Perl) and others are available as third-party add-ons.
Versions
ASP has gone through four major releases:
- ASP 1.0 (distributed with IIS 3.0) in December 1996,
- ASP 2.0 (distributed with IIS 4.0) in September 1997,
- ASP 3.0 (distributed with IIS 5.0), and
- ASP.NET (part of the Microsoft .NET platform). The pre-.NET versions are currently referred to as "classic" ASP.
- ASP.NET2
ASP.NET introduced the ability to replace in-HTML scripting with full-fledged support for .NET languages such as Visual Basic .NET and C#. In-page scripting can still be used (and is fully supported), but now pages can use VB.NET and C# classes to generate pages instead of code in HTML pages.
Examples
Pages can be generated by mixing server-side scripting code (including database access) with HTML and client-side code. For example:
Code:
<% ' This line does nothing, it's just a comment; the next line does: Response.Write("Wikipedia") ' This code writes out "Wikipedia" to the browser. %>
Code:
<% ' No way of changing the value of X. Dim X ' Make sure to always Dim your variables. X = 1 ' X is our variable in this example. If X = 1 Then %> <b>X equals one.</b> <% Else %> <b>X is not one.</b> <% End If %>
The code between the <% ... %> delimiters will be processed by the server. The resulting HTML is <b>X equals one</b> when the server-side variable X = 1.
For more efficiency, it is best not to open and close asp tags <% %> often, as this causes the ASP engine to have to turn on and off.
- For example, a more efficient solution would be:
<% Dim strWikiPedia strWikiPedia = "free" ' This example uses pure ASP VBScript to get the job done... If strWikiPedia = "free" then Response.write "Stick around and enjoy without entering in a credit card." Else Response.write "Get out your credit card. Or click a banner." End If %>
Now that we have covered "constant variables", lets worry about the request object. The request object is a very interesting one, it can read data from the "query string" or from the "form" that submitted to it. But for that you need to understand the difference between "post" and "get". "get" places the variables into the querystring (Request.QueryString()). "post" places the variables into the form (Request.Form()) here is an example.
Code:
<form action="pagename.asp" method="get"> <input type="text" name="Name" /><br /> <input type="Submit" /> </form> <% ' This line does nothing, it's just a comment; the next line does: strName = request.querystring("Name") If strName <> "" Then ' If the variable "strName" is not equal to "" (nothing) then ' The next line writes out "Welcome to Wikipedia", ' then the name of the person, to the browser. Response.write "Welcome to Wikipedia " & strName ' Important note: In the line above you will notice ' there is an extra space in the string, that makes ' sure that the name and the string don't get run ' together. End If %>
That code will ask for your name, when you press "Submit" it will reload the page and display your name, then welcome you to Wikipedia.
External links
- w3schools ASP Tutorial (http://www.w3schools.com/asp/default.asp)
- Microsoft's ASP.NET Homepage (http://msdn.microsoft.com/asp.net/)
- News article: PHP passes Microsoft Active Server Pages (http://newsforge.com/newsforge/02/06/11/011243.shtml?tid=5)
- Oracle review of PHP vs ASP.NET (http://www.oracle.com/technology/pub/articles/hull_asp.html)
- Webmaster.org: ASP Hosting Plans (http://www.webmaster.org/webhosting/plans/asp.htm)
- 4GuysFromRolla.com - Forum Site (http://www.4guysfromrolla.com/)
- ASP 101 - Tutorials, Articles, and Sample Code (http://www.asp101.com/)
- ASP Articles and Tutorials (http://www.aspdev.org/)
- ASPexplore - The system to run ASP sites off-line as applications (http://www.aspexplore.com/)
- ASP & MySQL Database Tutorial (http://www.vzio.com/tutorials/mysql_database.asp)da:Active Server Pages
de:Active Server Pages es:Active Server Pages fi:ASP fr:Active server pages it:Active Server Pages he:ASP nl:Active Server Pages ja:Active Server Pages no:Active Server Pages pt:ASP ru:ASP sv:Active Server Pages tr:ASP zh:Active Server Pages