IE8 and jQuery 1.4 have been on the street for a while now. My project which uses jQuery 1.4.1 and is about to start seeing IE8 users. So how's that been going for folks?
(I am interested in answers that identify issues, pitfalls, considerations, etc, as opposed to yep-working-good-for-us.)
You might start at http://docs.jquery.com/Known_Issues and then work your way to the jQuery trac reports at http://dev.jquery.com/report.
jQuery and IE8 work just fine :) There's not a lot of IE specific code in jQuery; it has used feature detection for a while now. This means it's looking for "can this browser do this?", rather than "is this browser x? then I'll assume it can or can't do this".
That being said, there are checks in jQuery core that wouldn't exist it it weren't for IE quirks, but they may or may not be IE specific....rather they're for how a particular browser handles the DOM.
The biggest issue with jQuery 1.4.1 I see on SO often is the change event in IE7 and IE8 I believe, mainly not working with .live(). It just gives generally odd behavior in some cases: unbinding isues, not propagating, etc. The solution? jQuery 1.4.2, it fixed a lot of issues (including those) and included an event module re-write. From the 1.4.2 release notes::
The largest internal changes have come through a much-needed structural rewrite of the events module. Many quirky issues related to event binding have been resolved with these fixes.