Tiny event delegation and event binding by extending Element with Element.prototype.on. Depends upon `matchesSelector`. Polyfill here: https://gist.github.com/3062955

Element.on.js

(function(El) {
  El.on = function(type, el, callback) {
    if ('function' === typeof el) {
      callback = el
      el = null
    }

    this.addEventListener(type, function (e) {
      if (!el || e.target.matchesSelector(el))
        return callback(e)
      }, false)
  }
}(window.Element.prototype));

Element.on.min.js

(function(El){El.on=function(type,el,callback){if('function'===typeof el){callback=el;el=null}this.addEventListener(type,function(e){if(!el||e.target.matchesSelector(el))return callback(e)},false)}}(window.Element.prototype));