JS "trycatch工厂模式"

大家都用过Ajax的异步交互，下面的代码中使用  "trycatch工厂模式"  来进行针对Ajax请求对象的变化点进行封装

<script type="text/javascript">
	var createHttpRequest = function() {
		var GetHttpRequest = [
			function() {return new ActiveXObject("Microsoft.XMLHTTP");},
			function() {return new XMLHttpRequest();}
		];
		for(var ele in GetHttpRequest) {
			try {
				GetHttpRequest[ele]();
			} catch {
				continue;
			}
			this.createHttpRequest = GetHttpRequest[ele]();
			return GetHttpRequest[ele]();
		}
　　　　　 throw new Error("这些对象都不能用！");
	}
  </script>