function gaga(){
	function createXHR(){
		if( typeof XMLHttpRequest != "undefined" ){
			return new XMLHttpRequest();
		}else if( typeof ActiveXObject != "undefined" ){
			var version = [
				"MSXML2.XMLHttp.6.0","MSXML2.XMLHttp.3.0","MSXML2.XMLHttp"
			];
			for( var i = 0; i < version.length; i++ ){
				try{
					return ActiveXObject( version[ i ] );
				}catch( e ){
					// 跳过
				}
			}
		}else{
			throw new Error( "您的浏览器不支持XHR对象！" );
		}
	}

	var xhr = new createXHR();   // 创建xhr对象
	xhr.open( "get","demo.PHP?rand=" + Math.random(),false );  // ?rand=" + Math.random() 防止ie下面的取到的值是缓存中的值
	xhr.send(null);
	var ga = xhr.responseText;   // 打印服务器返回来的数据
	// alert(ga); 
	if( xhr.status == 200 ){
		alert(xhr.status)
		alert(xhr.statusText)
	}else{
		throw new Erro( "获取到错误信息：" + xhr.status + "，错误信息：" + xhr.statusText )
	}
}
$(function(){
	$("body").click(function(){
		gaga();
	})
})