Firefox 15 Coming With Souped-Up Debugger

Firefox 15 has hit the Mozilla pre-beta Aurora channel, and it features a redesigned, built-in debugger.

Mozilla has released Firefox 15 to its pre-beta Aurora channel and the new release comes with some major new features and improvements to the built-in tools for Web developers.

Perhaps the biggest change in Firefox 15 is that it ships with a debugger that developers can use to find issues with their JavaScript code. The debugger is available via the Web Developer menu.

In a blog post, Kevin Dangoor, product manager for developer tools at Mozilla, said the Firefox debugging interface has been redesigned for Firefox 15. Dangoor wrote:

"This new debugger is not just a new user interface over the functionality that Firefox€™s JavaScript engine (SpiderMonkey) has been providing to tools like Firebug for years. The entire debugging interface in SpiderMonkey has been completely redesigned. There are two big things that Web developers get because of the new debugger back-end:1. It€™s fast! JavaScript applications running with the debugger open will run nearly as fast as they do without the debugger.2. It€™s remotable! You can connect the debugger user interface to a debugger back-end running somewhere else."

The second point above is exciting, because it means that you€™ll be able to debug JavaScript that is running in Firefox for Android or Firefox OS, all from the comfort of Firefox on your desktop or laptop computer.

Other new features in Firefox 15 include a new Responsive Design View that makes it easy to resize just the page the developer is viewing. €œWith the Responsive Design View, you can work on your designs without constantly pulling out your mobile phone to see how it looks,€ Dangoor said. €œAnd, you can try out your designs without shrinking your browser€™s tools, toolbars and other tabs.€

Firefox 15 also features a new Layout View that enables developers to see how the margins, padding and border are set for a node in one view. The Layout View is collapsed to a single line showing the developer the size of the element. It is available as part of the Style Inspector. Meanwhile, enhancements to the Page Inspector enable developers to turn off highlighting behavior.

In addition, Mozilla has given the Firefox 15 Web Console a major boost in performance, Dangoor said. The Web Console is like a heads-up display for the Web, enabling developers to view error messages and other logged information. In addition, there are methods developers can call to output information to the console, making it a useful debugging aid, and developers can evaluate JavaScript on the fly, Mozilla said.

The Firefox Aurora channel is where users and developers can go to preview features of what is in store for upcoming versions of the Firefox browser. Users and developers can share their experiences with the pre-beta software and help shape the final product. Mozilla announced on June 5 the availability of Firefox 13, the latest version of its desktop browser for Windows, Mac and Linux. And on July 7, Mozilla released the latest beta of Firefox 14. According to Mozilla€™s rapid release cadence, new releases are planned for every six weeks. Firefox 14 is expected to be generally available in mid-July.