[Javascript] detecting a frame with a field

Fri Oct 15 04:05:50 CDT 2004

Morning Terry,

You'll have difficulties if the documents in the two frames are served 
from different domains - you'll get "Access Denied" errors in javascript 
when trying to access the right-hand frame.

I know that you haven't said that they are below, but when you said that 
the right hand frame wasn't under your control, I thought that might 
have been one of the possibilities.

Assuming that the two documents are from the same domain however, I 
suppose you could use the setInterval () method of the left hand window 
to call a function every so often which checks the right hand frame. 
The function could use the getElementsByName method of the document in 
the right hand window.

Something like:

// ------------
function fCheckFrame () {
   oRightHandDocument = parent.idOfRightHandFrame.document;
   aElements = oRightHandDocument.getElementsByName ('CO_USERNAME');
   if (aElements.length > 0) {
     document.forms[0].submit ();
   }
}

window.setInterval (fCheckFrame, 100);
// -------------

You would need to know the ID and/or name of the right hand frame, but 
you'll have control over that won't you? Also you'd need to customise 
the reference to your form - I just used form[0] to reference the first 
(only) form in the document in my test case.  I've tested this in 
IE6/Win and Firefox and both are OK.

Hope this helps a little.  I'd be interested to see if anyones got a 
better method of triggering the check of the right hand frame, as I 
don't particularly like window.setInterval - it strikes me as (in this 
instance) a little inelegant.

Ta ta,

Matt

Terry Riegel wrote:
> Hello All,
> 
> I have set up a 2 frame page. The left frame is fully under my control, 
> the right frame is not.
> 
> +--+------+
> |  |      |
> |  |      |
> |  |      |
> +--+------+
> 
> I want the left frame to watch the right frame until it contains a form 
> with a text field named CO_USERNAME
> 
> The Right frame (I can't control its contents) will look like below.
> <body>
> <form method=post action=http://www.page.com>
> ...
> <input type=text name=CO_USERNAME size=30 maxlength=30 value="Visitor5">
> ...
> </form>
> </body>
> 
> When the left frame sees a text field labeled CO_USERNAME it will 
> trigger a page load.
> 
> 
> Can this be done?
> 
> Terry
> 
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