This is simply bind which will be in future versions of JavaScript. <a href="http://ejohn.org/blog/ecmascript-5-strict-mode-json-and-more/" rel="nofollow">http://ejohn.org/blog/ecmascript-5-strict-mode-json-and-more...</a> It has been available in dojo as dojo.hitch, goog.bind, $.hitch in a jQuery plugin.