js 写ajax

    function   test(){
        alert("123")
        var xhr = new XMLHttpRequest();
//发送异步请求
        var url='/efficiency/web/selectDeptByCity';
        xhr.open("GET",url,true);
        //发送请求
        xhr.send();
       xhr.onreadystatechange=function () {
           // 通信成功时，状态值为4
           if (xhr.readyState === 4){
               if (xhr.status === 200){
                alert(xhr.responseText);
                   console.log(xhr.responseText);
               } else {
                   console.error(xhr.statusText);
               }
           }
       }

原文https://blog.csdn.net/u012060033/article/details/89958461

标签：function,console,js,xhr,ajax,var,responseText,alert
来源： https://www.cnblogs.com/cuiguangpeng/p/13524679.html