Firefox Developer Edition is a new version of the popular browser Mozilla, focused on web developers.

In recent years the most popular browsers have built-in tools that allow to view and edit the source code of the web pages. This type of tools are very useful for web developers, since it allows to localize errors easily, edit the web page on the fly, and therefore see immediate results of the changes.

Firefox Developer Edition is a standard web browser, so we will be able to browse the Internet on the usual way, but it has the peculiarity that includes a multitude of tools that facilitate the work of the web developers. Some of these tools are:

• Valence: this tool allows is to debug different browsers in different devices. For example, we can debug a web page running on a Safari at iOS, or running on a Chrome at Android. This allows connecting the mobile device to the computer, and make changes on the page source code using Firefox. These changes will be reflected in the connected mobile devices. This tool is on atesting phase, so it is not recommended to work with it in a consistent way.
• Responsive design: thanks to this view it will not be necessary to install any plug-in to check how the page is viewed in many resolutions. This way, we can see if the responsive design adapts perfectly to the maximum number of possible resolutions.
• Page Inspector: this panel displays information about the elements that make up the web page. We can see and modify the HTML and CSS code on the fly. For example, if we select a CSS class, we will see highlighted in the web all the elements that make use of that CSS class. The same happens with the HTML code, when we open the “Inspector Page” panel and place the cursor on top of an HTML element, this element will be highlighted on the design of the page.
• Web Console: this panel shows the errors and warnings messages generated by the web page that we are visiting, and organizes them into categories, so we can see the correponding errors to CSS, Javascript, Network, etc., we can also interact with the elements of the web by typingJavascript code on the console. We will be able to call the method of an object, or use jQuery to list a series of items. Any thing we can do on Javascript, can be performed directly on the “Web Console”.
• Network Monitor: here we can see all the requests performed by a web page, and explore the headers of the same. This view is very useful to know exactly how many external elements is loading a web, and if it is necessary to reduce the number of elements. We can filter the requests by type: HTML, CSS, JS, Image, Sources, Multimedia, and other.

These are just some of the features that this new version of Firefox browser presents. Sure many web developers will be happy with this version, and will make Firefox Developer Edition his default browser.