[javascript]
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 new ActiveXObject( version[ i ] );
}catch( e ){
// 跳过
}
}
}else{
throw new Error( "您的
不支持XHR对象！" );
}
}
// 异步
$(function(){
$("body").click(function(){
var xhr = createXHR();
xhr.onreadystatechange = function(){
if( xhr.readyState == 4 ){ // 判断是否已经接受到全部响应数据
if( xhr.status == 200 ){ // 判断是否返回成功
alert( xhr.responseText );
}else{
throw new Error( "数据返回失败！状态代码：" + xhr.status + ",状态信息是:" + xhr.statusText );
}
}
}
xhr.open( "get","demo.php?rand=" + Math.random(),true );
xhr.send(null);
// xhr.abort(); // 取消异步请求
});
});
