JS在当前页面插入<script>标签,并执行

var htmm =document.getElementsByTagName("html")[0];
var scri = document.createElement("script");
scri.async="async"
scri.src="http://www.xxx.com/dummy.js"
scri.onload=function(){console.log("script onloaded");}
htmm.appendChild(scri);

Result:
  <script async src=?"http:?/?/www.xxx.com/?dummy.js">?</script>?
  dummy.js dummy.js:1
  script onloaded