/* Extra function */

Element.implement({
		//implement show
		show: function() {
			this.setStyle('display','inline');
		},
		//implement hide
		hide: function() {
			this.setStyle('display','none');
		}
	});
	
String.prototype.replaceAt = function(index, char) {
      return this.substr(0, index) + char + this.substr(index+char.length);
   };
   
   Function.prototype.bind = function(scope)
	{
		var _function = this;
				return function()
				{
				return _function.apply(scope, arguments);
				};
	};