Firefox 3.0 recorded usage share of web browsers. Estimates of Firefox 3.0's global market share were generally in the range of 4–5%, and then dropped as users migrated to Firefox 3.5 and later Firefox 3.6. Partially as a result of this, between mid-December 2009 and the end of January 2010, Firefox 3.5 was the most popular browser (when counting individual browser versions), passing Internet Explorer 7. Mozilla ended support for Firefox 3 on March 30, 2010 with the release of 3.0.19. Firefox 3.0 was developed under the codename "Gran Paradiso". This, like other Firefox codenames, is the name of an actual place;
JavaScript differences between the various browsers (particularly within the DOM), it is useful to have access to a debugger for each of the browsers that a Web application targets. Script debuggers are integrated within Internet Explorer, Firefox, Safari, Google Chrome, Opera and Node.js. In addition to the native Internet Explorer Developer Tools, three debuggers are available for Internet Explorer: Microsoft Visual Studio is the richest of the three, closely followed by Microsoft Script Editor (a component of Microsoft Office), and finally the free Microsoft Script Debugger that is far more basic than the other two. The free Microsoft Visual Web Developer