<!DOCTYPE html>
<html lang="en">
<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>
//手写ajax
let xhr = new XMLHttpRequest;
xhr.open("POST", "http://jspang.com/DemoApi/oftenGoods.php", true);
xhr.onreadystatechange = function () {
if (xhr.readyState == 4 && xhr.status == 200) {
console.log(xhr.responseText)
}
}
xhr.send()
</script>
</html>
//================================================
<!DOCTYPE html>
<html lang="en">
<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>
//手写ajax
var xhr = new XMLHttpRequest()
xhr.open('POST', "http://jspang.com/DemoApi/oftenGoods.php", true)
// false就是等待有返回数据的时候再继续往下走，还没有得到数据的时候就会卡在那里，直到获取数据为止。
// true就是不等待,直接返回，这就是所谓的异步获取数据！
xhr.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
xhr.onreadystatechange = function () {
if (xhr.readyState == 4) {
if (xhr.status == 200) {
console.log(xhr.responseText)
}
}
}
xhr.send()
</script>
</html>