Object.extend(Object.prototype, {
	classNameOn : function (selector) {
		this.className += " " + selector
	},
	classNameOff : function (selector) {
		this.className = this.className.replace(selector, "")
	},
	toggleClassName : function (selector) {
		if(this.className.search(selector) != -1)
			this.classNameOff(selector)
		else
			this.classNameOn(selector)
	}
});