The difference is that MooTools and Prototype modify the built in Function. Because of this, old versions of MooTools, and Prototype don't play nice with curre

The difference is that MooTools and Prototype modify the built in Function. Because of this, old versions of MooTools, and Prototype don't play nice with current browsers. This a a big reason jQuery won the war. function() {}.bind() is more convenient and cleaner, but $.proxy() will work regardless of whether Microsoft incorrectly implements a built in bind in their latest browser.