The easiest way to check your site at different screen resolutions
There are still a few folks out there with old 800 x 600 pixel monitors, and if you want to take that into account when designing your website, you can use this handy trick to quickly see what any site looks like at different resolutions. Simply copy and paste the following Javascript into the Location bar of your browser and hit enter while viewing the site in question. The following bit will resize your browser to 800 pixels wide and 600 pixels high. You can change the width and height to any other resolution you’d like to test as well.
javascript: self.resizeTo(800, 600);
I’ve also created a quick bookmarklet. Take this link: 800×600, and drag it to your bookmarks/links toolbar and then click it to resize your window to 800 x 600 pixels.