QUICK HIT: No More IE Workarounds in jQuery 3
There will no longer be support for older Internet Explorer workaround in the latest version of jQuery (v3.0).
Those designers/developers who still need to work with IE6, IE7 and IE8 should continue using jQuery 1.0 for the foreseeable future. After 18 months of development, jQuery has created a slimmer, faster version with backwards compatibility in mind. The version is being positioned as a continuation of the 2.x branch, but with a few major changes that were long overdue.
The team being jQuery also released a "slim" version that excludes Ajax and effects modules (as well as deprecated code.