Problem in loading Iframe in FireFox!

Question

Hello all,

I'm trying to load an aspx page using Iframe in VB.net. I'm trying to do it(setting the source of Iframe) with the help of Ext(JavaScript). aspx code:

< div id="container" >
 < iframe id="pane" name="pane" src="Empty.aspx" frameborder="0" >< /iframe>
< /div >

Javascript code:

Pane = function() {
    var pane;
    return {
        init: function() {
            if (!document.body) { return; }
            pane = Ext.get('pane');
            if ( something ) {
                this.load();
            } else {
                this.navigateTo('Page.aspx?id=' + a.ID);
            }
        },
        load: function() {
            pane.dom.src = 'HTTPURL';
        },
        navigateTo: function(url) {
            var agt = navigator.userAgent.toLowerCase();
            if (agt.indexOf("firefox") != -1) {
                document.getElementById('pane').src = url;
            } else {
                pane.dom.src = url;
            }
        }
    };
} ();

This works fine with IE and Ifrma gets loaded wuth page.aspx every time the parent page is requested. But with FireFox it doesn't. With FireFox the src attribute remains "Empty.aspx" when the page is loaded but when i refresh the page i.e. in post back event the scr attribute changes to "page.aspx?id=a.id" and iframe gets loaded properly.

Has anyone faced such kind of problem before? and knows the solution please help me, it's killing me big.

Thanks in Advance. Maddy.