[Javascript] Re: Javascript probem in HTML Form

[Roger Roelofs]

Saurabh,

On May 21, 2004, at 6:57 AM, saurabh sinha wrote:

> Now if any button (e.g. Football) is selected by user then after 
> clicking on Submit button the radio button 'Football' should be shown 
> as checked. (Code is given below)
>  ...<snip>... 
>
> <form name="form1">
> <input type="radio" name="rd" value="FOOT"/>Football
> <br />
> <input type="radio" name="rd" value="CRIC"/> Cricket
>  <input type="Submit" value="Submit" />
> </form>
>  
> JavaScript Code:
>  
> function on_submit() {
> var qry=location.search.substring(1,location.search.length);
> var aa=qry.indexOf('Qstring=');
> alert(aa);
> if(aa!=-1) {
> 	var ss=qry.substring(aa+11,aa+17);
> 	alert(ss);
> 	if(ss=="FOOT") {
> 		form1.rd[0].checked=True;
> 	} else {
> 		form1.rd[1].checked=True;
>  	}
> }
> }
>  
> I am calling the function 'on_submit()' from <input type="Submit" 
> value="Submit" onclick="'on_submit()"/> but not getting the result.

Either you are a bit unclear about how web forms work or I'm not 
understanding your email.  I highly reccomend the current edition of 
O'Reilly's 'Javascript: The Definitive Guide' if javascript is new to 
you.  We could be more helpful if you could post a url to this page.

During the onsubmit phase, the state of the radio buttons only exists 
in those radio buttons.  When the furm is sent to the server for 
processing, if the form method is 'get' the browser will create the 
querystring based on the form field values.  So, if the javascript is 
from the same page as the form, the querystring will be empty.  If the 
javascript is on the 'receiving' page, set in the form's action 
attribute, I'd recommend using one of the may url parsing scripts 
available at the usual script repositories.

hth,

Roger
-------------------------------------------------------
Roger Roelofs                 web   www.datacompusa.com
Datacomp Appraisal Services   web   www.mhvillage.com
3215 Eaglecrest Drive, NE     Email rer at datacompusa.com
Grand Rapids, MI  49525-4593