asynchronous Form w/ Iframe Target -- OnLoad works in FF, Chrome, IE9, doesn't get response in IE7
===

I have an ajax-style form in a popup window in my app. I use a form with a target iframe, then on the iframe.load() function, I take the contents and display them back into my popup.

This works on IE9, Chrome, Firefox:

     $("iframe[name=addpart-iframe]").load(function () {
                //FF and IE fire the load when the popup first load, chrome does not. This kips the first onload where no submit has happened yet
                   if (firstLoad == true) {
                       firstLoad = false;
                       return;
                   }


                   var response = this.contentDocument.body.innerHTML;
                   $("#AddForm").html(response);


               });       

This works great, except in IE7. When I look at this.contentDocument.body -- the debugger says that body is not a valid property. I look at the outer HTML, and my iframe is also empty at this time. Not sure why!
