一个简单的小技巧，监控网页所有动态标签创建的调用处

<script>
      console.log("Jerry");
      var scripts = document.querySelectorAll("script");
      var old = document.createElement;
      var _this = window.document;
      document.createElement = function(input){
        console.log("trying to create new tag: " + input);
        return old.call(_this, input);
      }
      debugger;
    </script>