原生ajax

时间 2019-12-25
标签原生 ajax 栏目 Ajax 繁體版
原文原文链接
<!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，尚未获得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>