js文件里追加别的js

var newScript=document.createElement("script");
              newScript.type="text/javascript";
              newScript.src="../script/base64.js";
var md5Script=document.createElement("script");
              md5Script.type="text/javascript";
              md5Script.src="../script/md5.js";
var head=document.getElementsByTagName("head")[0];
    head.appendChild(newScript);
    head.appendChild(md5Script);