When you’re developing a web site then it’s important to check how your pages are displayed in all the main browsers. But that’s not always straightforward, especially with IE, as you can’t easily install multiple versions on the same system.

Fortunately there’s a simple alternative in Microsoft’s Express Web SuperPreview, an Expression Web component that’s also available as a stand-alone trial version. The latest version has just been released and it makes a very useful addition to every web developer’s testing toolkit.

By default SuperPreview can render your URL of choice in IE6, IE7, IE8 (both regular and compatibility views) and Firefox. But if you register for Microsoft’s SuperPreview online service beta (just a matter of submitting and confirming your email address) then you’ll also be able to view a page in IE9, Chrome, and Safari 4 and 5.

And once set up, essentially all you have to do is choose the two browsers that you’d like to compare, enter a URL, and watch as the pages are rendered, side by side. There’s an option to overlay the pages, which will quickly reveal whether you’ve achieved that pixel-perfect alignment that you’re after. And if there’s a problem, then the built-in DOM and CSS inspectors will help to locate it for you.

This is only a trial version, though, and so after 60 days you’ll lose ability to render pages using Firefox, or the remote browsers (IE9, Chrome, and Safari 4 and 5). Microsoft are clearly hoping that you’ll buy a copy of Expression Web (yours for $149) to get this back, but even if you don’t, the expired SuperPreview trial will still allow you to compare URLs using IE6, 7 and 8, and we think that’s enough to justify its place on most developer’s desktops.