I came across this issue because I was using $.load with a selector like 'root > li', and it worked on FF, Safari but on IE6 it didn't. (I haven't tested IE7.)

So I narrowed it down to selectors and made a nice test case for you guys using basically the same method .load uses to insert html to the target element.

It seems to boil down to this, given a string s = <root><span><b>Examplicious</b></span></root>

selector 'root' will be found.

selector 'b' will be found.

selector 'root > span' will not be found because it names two elements, one which isn't a valid HTML element.

Check the attached test case in different browsers for more examples.