By Gregg Keizer
October 8, 2008

Mozilla Corp. will use a several-week delay it recently added to the Firefox 3.1 schedule to build a private browsing mode and beef up the browser's address bar, the company said today.

Three weeks ago, the company said it would insert four to five more weeks into the timetable, part of a reaction to changes in the browser market, including the introduction by Google Inc. of its Chrome browser. Then, Mozilla said it would probably use the time to add a privacy mode and to punch up its TraceMonkey JavaScript engine performance.

A private browsing mode and fast JavaScript execution were touted by Google last month when it launched Chrome. In meeting notes published on its Web site today, Mozilla said it planned to add the privacy feature in Beta 2, which would likely be released in November according to Mozilla's current schedule.

Dubbed "porn mode" by some, privacy tools limit or entirely eliminate what the browser records as it travels the Internet. Typically, URLs are not recorded in the history, cookies are not saved and other evidence is purged from the computer at the end of the session. Microsoft Corp.'s Internet Explorer 8, Chrome, and Apple Inc.'s Safari all have private browsing built in.