- Sizzle Selector Engine: The new CSS selector engine (nicknamed Sizzle") is faster than the current engine (49% faster in fact), standalone and fully extensible.
- Live Events: jQuery now supports "live events" (events that can be bound to all current and future elements using event delgation and a seamless jQuery-style API.
- jQuery Event Object: The event system for jQuery has been refactored, and now encapsulates all of the functionality found W3C-compliant event object implementation and makes it work smoothly across all browsers.
- HTML Injection Rewrite: Code related to injectiving HTML into a document has been overhauled. Append, prepend, and before and after methods are now much faster. The creation of DOM elements has also been modified.
- Offset Rewrite: The offset method was completely rewritten and now handles cross-browser issues better and faster (3x improvement in performance).