Microsoft Expression Web SuperPreview is intended to help you debug web pages without running multiple instances of different versions of Internet Explorer or had to wait for a web service to return renderings of your pages. It’s a challenge for every web developer to check website compatibility across a bunch of browsers and browser versions existing today. Until now, either you could install every browser, verify the website via a visual inspection and debug with tools specialized to that browser, or you could send a URL to a third-party screenshotting service like BrowserShots for an all-in-one visual inspection.

Expression Web SuperPreview for Windows Internet Explorer is a stand-alone visual debugging tool that makes it faster and easier to prove your sites look and work the same in IE6, IE7, IE8 or other browsers you may have installed locally such as Firefox 3.5, Safari 3, Safari 4 and even a bitmap websites mockup.  You can view the pages side by side or as an onion-skin overlay and use a standard set of modern HTML debugging tools like a DOM inspector, CSS inspector, element highlighting, pixel rulers and guides to precisely identify differences in layout. To help you quickly identify problem elements, DOM highlighting shows absolute positions of the rendered elements and HTML elements display CSS properties.

Update The final version of Microsoft Expression Web SuperPreview is out and can be downloaded from Microsoft.com. It only supports renderings between IE6 and versions of IE already installed on your computer, but it should ease the pain of cross browser development and testing for IE6/7/8 compatibility. If you need to test the site layout not only in IE but in Firefox, Microsoft Expression Web should be installed on your computer.