SuperPreview is a tool from Microsoft that lets web developers test websites and debug layout issues across different web browsers, by viewing their pages in multiple browsers simultaneously.
Testing websites on different browsers is often a pain, and at times impossible. Most browsers can’t have multiple versions installed side-by-side, for one reason. The newest version replaces older versions. So, you can’t have IE6 and IE7 on the same machine. One way is to use online services like Browsershots, but these are slow.
SuperPreview solves this problem by letting you view your pages in a variety of different browsers. Most online browser tools show you only images of different browser renderings. SuperPreview, on the other hand, couples image renderings with DOM data, letting you highlight specific DOM elements within the image, and showing you differences across browsers. It also provides element information such as position, dimensions and ID. This helps you pinpoint the element that’s causing the compatibility issue. You can use rulers and guides to measure and highlight visual problems, zoom in and out of a page and see all the browser renderings update in tandem.
SuperPreview is still under development and when it’s complete, it will be a part of future releases of Expression Web. However, a beta version of SuperPreview for Internet Explorer is available. This free download will allow you to compare renderings of IE6 with whatever other version of IE you have installed on your machine. If you have installed IE8, you’ll be able to compare IE6, IE8 and IE8 running in IE7 compatibility mode, side-by-side. The final version is likely to include all installed browsers on the system like Firefox, Chrome, Opera etc, as shown in the screenshot.
Here are some other ways of testing websites on different versions of IE.