封装ajax

封装方法

  function ajax(method,url,data,success){//方法,路径,参数,函数
    var xhr=null;
    try{
        xhr=new XMLHttpRequest();
    }catch(e){
        xhr=new ActiveXObject("Microsoft.XMLHTTP");
    }
    if(method=='get' && data){
        url+="?"+data;
    }
    xhr.open(method,url,true);
    if(method=='get'){
        xhr.send();
    }else{
        xhr.setRequestHeader('content-type','application/x-www-form-urlencoded');
        xhr.send(data)
    }
    xhr.onreadystatechange=function(){
        if(xhr.readyState==4){
            if(xhr.status==200){
                success&&success(xhr.reponseText)
            }else{
                alert("err"+xhr.status)
            }
        }
    }
}

调用示例

 btn.onblur = function() {
    ajax('get', 'index.php', 'm=index&a=verifyUserName&username=' + this.value,   function(data) {
    var d = JSON.parse(data);
    oVerifyUserNameMsg.innerHTML = d.message;
        if (d.code) {
            oVerifyUserNameMsg.style.color = 'red';
        } else {
            oVerifyUserNameMsg.style.color = 'green';
        }
    });
}