The excanvas library is an add-on, which will add the HTML5 canvas functionality to the old IE browsers (IE7-8).Firefox, Safari and Opera 9 support the canvas tag to allow 2D command-based drawing operations.
ExplorerCanvas brings the same functionality to Internet Explorer. To use the HTML5 canvas element in IE, include the ExplorerCanvas tag in the same directory as your HTML files, and add the following code to your page in the head tag.
<!--[if lte IE 8]> <script src="excanvas.js"></script> <![endif]-->