SuperPreview changes the way to test rendering on multiple browsers

If you haven’t seen this technology, check out the MIX Day 1 Keynote video. Very cool stuff. Now, you can download a trial edition of Expression to try this out.

Expression Web SuperPreview for Internet Explorer is a stand-alone visual debugging tool that makes it faster and easier to migrate your sites from Internet Explorer 6 to Internet Explorer 7 or 8. With Expression Web SuperPreview for Internet Explorer, you can ensure that your Web sites work correctly in Internet Explorer 8 while also maintaining compatibility with earlier versions of Internet Explorer.

Expression Web SuperPreview for Internet Explorer shows your web pages rendered in Internet Explorer 6 and either Internet Explorer 7 or Internet Explorer 8, depending on which version you have installed on your machine. You can view the pages side by side or as an onion-skin overlay and use rulers, guides and zoom/pan tools to precisely identify differences in layout. You can even compare your page comp to how the targeted browsers render the page.
To help you quickly identify problem elements, DOM highlighting shows absolute positions of the rendered elements and HTML elements display CSS properties.