Developing and Debugging in IE 8
"In some ways tools are the best things developers have in the face of browsers that behave differently," Hachamovitch said. Moreover, "Microsoft contributed 2,500 tests to the W3C [World Wide Web Consortium] so that people can ensure that CSS 2.1 [Cascading Style Sheets] work right, and with RC1 we're going to contribute 1,000 more. It's like playing scales-if you can't play the scales, you can't play the music right," Hachamovitch said. He said these tests are important "because browsers can behave so differently, so these CSS tests are crucial."
The IE 8 tools also provide a visual interface to the platform. As Shaan wrote:
Ben Galbraith, one of the co-directors of the recently formed Mozilla Developer Tools Lab, said Microsoft has implemented an integrated set of developer tools inside of IE 8 that strongly resemble both the interface and capabilities of Firefox's wildly popular "Firebug" plug-in. He said he and the co-director of the Mozilla tools lab, Dion Almaer, "couldn't be more happy to see this happen. I haven't taken a close enough look at it to compare it to Firebug in any detailed way, but it seems very handy indeed." Galbraith added:In addition to simplifying the debugging process, IE 8 Developer Tools offer a new perspective on your site. Instead of just a source view, the tool provides visibility into Internet Explorer's internal representation of the site. For example, the DOM tree in the tool is built from the tree IE builds internally to display the page, not from your source. So if script changes the tree, IE 8 shows you the updated tree.