Firefox is loading IE6-only CSS stylesheets on AJAX requests. I'm using Firefox 3.6.3, and making an AJAX request that contains the following HTML (in the HEAD): This logic works fine in other browsers, and it works fine on regular page loads/sans-AJAX (i.e. the stylesheet is loaded ONLY in IE6). On AJAX requests, however, Firefox sees this line of code and loads the stylesheet via a GET request, applying my IE6 styles to the page. I have tried formatting the conditional code differently (lt IE 6, lte IE 6, IE 6, etc.), but I get the same result every time. I think this might be a bug in the latest version of Firefox (although I am unable to test on multiple versions of the browser at this time). Please let me know if there is anything I can do to work around this issue!