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);
}
}
}
}
}