This tool is for everyone who needs a quick and easy way to test their website design in multiple screen widths.

You can test any website, and provide the link to anyone you like by adding their URL to the end of the testing page address. For example: http://mattkersley.com/responsive?google.com

• Copy index.html and responsive.js onto your machine
• Update the defaultURL at the top of responsive.js to your own website
• Upload the files into a subdirectory on your server
• Navigate to the new subdirectory via a browser

Once you've uploaded, you can navigate your website from within the iframes, and the others will update. This won't work for external sites however due to browser security restrictions.