初学Ajax
封装一个简单的Ajax
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <title>Document</title> <script src="ajax.js"></script> <script> window.onload = function(){ var btn = document.getElementById(‘btn‘); btn.onclick = function(){ ajax(‘ab.txt‘,function(str){ alert(str); },function(failed){ alert(failed); }) } } </script> </head> <body> <button id="btn">发送</button> </body> </html>
function ajax(url,fnSucc,fnFaild){ // 1.创建ajax对象 if(window.XMLHttpRequest){ var ajax = new XMLHttpRequest(); } else{ // IE6, IE5 浏览器执行代码 var ajax = new ActiveXObject("Microsoft.XMLHTTP"); } // 2.连接服务器 // open(方法,文件名,异步传输) ajax.open(‘GET‘,url,true); // 3.发送请求 ajax.send(); // 4.接收返回值 ajax.onreadystatechange = function(){ // 有0,1,2,3,4值 if(ajax.readyState==4){ // 请求成功 if(ajax.status==200) { fnSucc(ajax.responseText); } else{ if(fnFaild){ fnFaild(ajax.status); } } } } }