Collection
Collection
![[Web front-end] Node.js quick start](https://img.php.cn/upload/course/000/000/067/662b5d34ba7c0227.png)
<!DOCTYPE html>
<html lang="zh">
<head>
<meta charset="UTF-8" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<meta http-equiv="X-UA-Compatible" content="ie=edge" />
<title>Document</title>
</head>
<body>
</body>
<script type="text/javascript">
//异步请求，是指主程序运行的过程当中，请求程序正常运行
//同步请求，主程序运行中，请求程序无法运行
//var ajax = new XMLHttpRequest();
//ajax.open('get','./ajax1.php',true);
//ajax.send();
//ajax.onreadystatechange = function(){
// if(ajax.readyState == 4 && ajax.status ==200){
// var result = ajax.responseText;
// alert(result);
// }
//}
//alert('可以弹出的啊');
//同步请求，主程序等待操作
var ajax = new XMLHttpRequest();
ajax.open('get','ajax1.php',false);
ajax.send();
var result = ajax.responseText;
alert(result);
alert('主程序代码');
</script>
</html>点击 "运行实例" 按钮查看在线实例
