I recently got a problem when upgrading to IE8.
Webpage error details User Agent: Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.1; WOW64; Trident/4.0; MathPlayer 2.10d; User-agent: Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; http://bsalsa.com) ; SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; Media Center PC 6.0; FDM) Timestamp: Thu, 14 Jan 2010 08:51:36 UTC Message: Object doesn't support this property or method Line: 3 Char: 5 Code: 0 URI: /umbraco_client/modal/modal.js
I posted a question about it on the Umbraco forum, and started troubleshooting on my own.
Old: ie6=$.browser.msie&&($.browser.version == "6.0") New: ie6=$.browser.msie&&($.browser.version == "6.0")&&!window.XMLHttpRequest
I thought this would solve my problems, but the issue was still there.
So I split the modal.js file into modal.js and modalhelpers.js, the former containing the jqModal script and the latter containing the Umbraco helper functions. I edited /umbraco/umbraco.aspx to load modal.js before loading modalhelpers.js, and voila! It worked!
<meta http-equiv="X-UA-Compatible" content="IE=EmulateIE7" />
I hope this will be fixed in the next Umbraco release, but for those in need of an immediate fix, try one of the above.