Mozilla delivers Firefox 3.5 Beta 4, boosts speed

Mozilla Corp. late yesterday released Firefox 3.5 Beta 4, the latest development preview of the company’s next browser, which has been delayed several times and now is tentatively slated to ship before the end of June.

The milestone features more work under the hood — particularly in stability and performance of the new TraceMonkey JavaScript engine — as well as tweaks to the private browsing mode and improvements to the underlying Gecko layout engine, said Mike Beltzner, director of Firefox.