script标签清除缓存

<script type="text/javascript">
(function(){ 
     var randomh=Math.random();
     var e = document.getElementsByTagName("script")[0];
     var d = document.createElement("script");
     d.src = "//site.com/js.js?x="+randomh+"";
     d.type = "text/javascript"; 
     d.async = true;
     d.defer = true;
     e.parentNode.insertBefore(d,e);
 })();
</script>

<script>document.write("<script type=‘text/javascript‘ src=‘//site.com /js.js?v=" + Date.now() + "‘><\/script>");</script>