Provided by Tim Nichols:

This happens on both IE7 and IE8 - if you make an ajax call and use html as your content type, the call fails. (text, json, and others work fine). It does not happen on IE6 or FF.

Work arounds:

Option 1- return text instead of html, then use:

success: function(data) {

xhr = (new DOMParser()).parseFromString(data, ‘text/html’);

…

}

Option 2- overload the jQuery.ajaxSetup() function.

// IE 7/8 fix for html ajax calls...

jQuery.ajaxSetup({ xhr:function() {

try {

if (window.ActiveXObject)

return new window.ActiveXObject("Microsoft.XMLHTTP");

} catch(e) {}

return new window.XMLHttpRequest();

}

});