You should check out SproutCore's CoreQuery: <a href="http://docs.sproutcore.com/symbols/SC.CoreQuery.html#constructor" rel="nofollow">http://docs.sproutcore.com/symbols/SC.CoreQuery.html#constru...</a><p>It's a subset of jQuery that they've extracted and baked in with the rest of SproutCore's UI elements. They've also introduced a way to design your UI with state charts (very cool).<p>Of course, there's also nothing preventing you from just using the full jQuery library with SproutCore.