callback.html

<!DOCTYPE html>
<html>
<head>
<meta name="application-name" content="snow white">
<meta name="generator" content="wang pin">
<meta name="description" content="OAuth github test">
<meta name="keywords" content="HTML,CSS,XML,JavaScript">
<meta name="author" content="wang pin">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<!--HTML4 charset def-->
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<!--HTML5 charset def-->
<meta charset="UTF-8">
<link rel="icon" href="/assets/icon.ico" type="image/x-icon">
<title>OAuth github test</title>
<style>
 body {
  margin: 0; /* Remove default margin */
 }
</style>
</head>
<body>

</body>
<script type="text/javascript" src="/ajax.js"></script> 
<script type="text/javascript">

  function getParameterByName(name, url) {
    if (!url) url = window.location.href;
    name = name.replace(/[\[\]]/g, '\\$&');
    var regex = new RegExp('[?&]' + name + '(=([^&#]*)|&|#|$)'),
        results = regex.exec(url);
    if (!results) return null;
    if (!results[2]) return '';
    return decodeURIComponent(results[2].replace(/\+/g, ' '));
  }

 document.addEventListener('DOMContentLoaded', function(){
   ajax('post', 'https://github.com/login/oauth/access_token', {
     client_id: '7480d3802f0259608aec',
     client_secret: '57a53a7ceb0d07807b3ef47c29a6b9954408422c',
     code: getParameterByName('code')
   },
   function(data){
     debugger
   },
   function(err){
     debugger
   })
 })
</script>
</html>