[JSP] postbacks - Tilted Forum Project - TFP - Sexuality, Philosophy and Political Discussion

NeoSparky · 06-21-2004, 03:49 PM

Is there anyway to check for a postback like in asp.net stuff in JSP's other than using querystrings and/or form submits?

DigitalD17 · 07-10-2004, 01:43 AM

not unless you're doing J#.NET (or whatever cockamamy thing MS has dreamed up to "take place" of Java for .NET). Postbacks are a completely proprietary function of ASP.NET languages.

Oh, Just so you know, Postbacks work through an actual form being submitted, and the server automatically checking to see that it was a special type of form being submitted that triggers the "postback"

manalone · 07-10-2004, 08:21 PM

what do they do?

Stompy · 07-13-2004, 11:51 AM

postbacks inform the server that an event took place.

for example, the code on a drop down menu will have a "__doPostBack" javascript attached to it on any of it's events (most common: onChange).

When the JS is called, the element's name is passed as an argument to a function which submits a form back to the server that triggers event handler code.

When the server is notified, that control's event handler fires.. so in your c# code, "cboBlah_OnChange" will fire. You can then add whatever code you need.

PostBacks, combined with ViewState, are awesome. Makes it very easy to change certain parts of your HTML without having to redraw the whole thing or execute unnecessary code.

It's kinda hard to explain, and it really didn't make much sense to me until I got very deep into user control creation. It's very handy.

06-21-2004, 03:49 PM	#1 (permalink)
NeoSparky Crazy Join Date: Oct 2003	[JSP] postbacks Is there anyway to check for a postback like in asp.net stuff in JSP's other than using querystrings and/or form submits?

07-10-2004, 08:21 PM	#3 (permalink)
manalone Once upon a time... Join Date: Apr 2003	what do they do? __________________ -- Man Alone ======= Abstainer: a weak person who yields to the temptation of denying himself a pleasure. Ambrose Bierce, The Devil's Dictionary.

07-13-2004, 11:51 AM	#4 (permalink)
Stompy Banned from being Banned Join Date: Aug 2003 Location: Donkey	postbacks inform the server that an event took place. for example, the code on a drop down menu will have a "__doPostBack" javascript attached to it on any of it's events (most common: onChange). When the JS is called, the element's name is passed as an argument to a function which submits a form back to the server that triggers event handler code. When the server is notified, that control's event handler fires.. so in your c# code, "cboBlah_OnChange" will fire. You can then add whatever code you need. PostBacks, combined with ViewState, are awesome. Makes it very easy to change certain parts of your HTML without having to redraw the whole thing or execute unnecessary code. It's kinda hard to explain, and it really didn't make much sense to me until I got very deep into user control creation. It's very handy. __________________ I love lamp. Last edited by Stompy; 07-13-2004 at 11:53 AM.

07-10-2004, 01:43 AM	#2 (permalink)
DigitalD17 Rookie Join Date: Jul 2004	not unless you're doing J#.NET (or whatever cockamamy thing MS has dreamed up to "take place" of Java for .NET). Postbacks are a completely proprietary function of ASP.NET languages. Oh, Just so you know, Postbacks work through an actual form being submitted, and the server automatically checking to see that it was a special type of form being submitted that triggers the "postback"