javascript SP2010 vs IE SharePoint 2010 is not really compatible with IE9. The master page forces it in IE8 compatibility mode. One of the odd quirks you will experience if you change the master page to IE9
ie JavaScript commas in IE While working with JQuery UI DataTables I got some strange JS errors in IE. And not from any-better-browser. 'style' is null or not an object My Google cortex provided the answer: IE javascript