If you’re getting an unreasonable “Expected Identifier” Javascript error on IE6/7, check to see if you have any variable names which are reserved words. This also goes for HTML form element names: <form name="aform"> <input type="text" name="name" /> </form> Then accessing document.aform.name.value would throw an error since name is a reserved word. Javascript Reserved Words abstract alert Anchor Area arguments Array assign blur boolean or Boolean break Button byte callee caller captureEvents case catch char Checkbox class clearInterval clearTimeout close closed comment confirm const constructor continue Date debugger default defaultStatus delete do document Document double Element else enum escape eval export extends false FileUpload final finally find float focus for Form Frame frames function Function getClass goto Hidden history or [...]

hoverIntent is a plug-in that works like (and was derived from) jQuery’s built-in hover. However, instead of immediately calling the onMouseOver function, it waits until the user’s mouse slows down enough before making the call. Why? To delay or prevent the accidental firing of animations or ajax calls. Simple timeouts work for small areas, but [...]

This experimental plugin for the jQuery UI datepicker widget looks promising: You can get it via SVN. Update: The Filament Group has also made a really cool datepicker.

XOR (exclusive OR) is a boolean operator, like && and ||, but with the following logic: It is successful if the expression on either side is true (like ||), but not if both sides are true (like !( x && y )). Sometimes, in your JavaScript, you might want to do the following: if( foo XOR bar [...]