js 判断ipad 直接用： sUserAgent.match(/ipad/i) == "ipad"; 即可。可以参看：js完美判断移动设备自动转跳移动网站代码 里面第一个函数也判断了ipad只是被我注释掉了

新浪官网js判断ipad函数范例

var SINA_ARTICLE_PAGE_SETTINGS = {
  comment: {
    group: 0,
    page: 1,
    pageSize: 20,
    showReplay: true,
    maxWordCount: 140,
    hotPageNum: 3,
    firstPageNum: 10,
    clickMoreTimes: 3
  },
  isPad: (function() {
    var arr = ["ipad", "mi-pad"],
      android = 'Android',
      len = arr.length,
      userAgent = navigator.userAgent.toLowerCase(),
      valid = false;
  
    for(var i=0;i<len;i++){
      var txt = (arr[i] + "").toLowerCase(),
      reg = new RegExp(txt,"i"),
      reg_android = new RegExp(android,"i");
      valid = (userAgent.match(reg) == txt && (txt == 'ipad' ? true : userAgent.match(reg_android) == android.toLowerCase()));
      if(valid === true){
        break;
      }
    };
    return valid;
  })()
};

前面这个函数判断是不是ipad的，如果是ipad的就加载指定的内容 如下

<script type="text/javascript">
 (function(){
   //var isTouchDevice = 'ontouchstart' in window;
   var _doc = document;
   var head, meta;
   if(SINA_ARTICLE_PAGE_SETTINGS.isPad){
     head = _doc.querySelector('head');
     meta = document.createElement('meta');
     meta.setAttribute('name', 'viewport');
     meta.setAttribute('content', 'initial-scale=1.0,maximum-scale=1.0,minimum-scale=1.0,user-scalable=no');
     head.appendChild(meta);
  
     _doc.write('<link rel="stylesheet" href="特定.css">');
     _doc.write('<' + 'script type="text/javascript" src="特定.js"></' + 'script>');
  
   } else {
     _doc.write('<link rel="stylesheet" href="特定.css">');
     _doc.write('<' + 'script type="text/javascript" src="特定.js"></' + 'script>');
   }
 })();
 </script>