デフォルトイベントとバブリングの抑制（旧IE対応）。

cancel.js

var cancelBubble,
	cancelEvent;

cancelBubble = (function () {
	var func = function () {};
	if (typeof Event !== 'undefined' && typeof Event.prototype.stopPropagation === 'function') {
		func = function (e) { e.stopPropagation(); };
	} else if (window.event) {
		func = function () { window.event.cancelBubble = true; };
	}
	return func;
}());

cancelEvent = (function () {
	var func = function () {};
	if (typeof Event !== 'undefined' && typeof Event.prototype.preventDefault === 'function') {
		func = function (e) { e.preventDefault(); };
	} else if (window.event) {
		func = function () { window.event.returnValue = false; };
	}
	return func;
}());