Font.js: A Powerful Font Toolkit for JavaScript
http://badassjs.com/post/16355968400/font-js-a-powerful-font-toolkit-for-javascript
Mike Kamermans has been working on a little font toolkit for your JavaScript that is kind of akin to the built-in Image object but for Fonts. It gives you font loading events using a technique perfected in Mozilla’s pdf.js project, metrics information, and a better version of the canvas element’s measureText method with additional information such as height, bounding box, and leading.