Google Scripts Move An Image
===

Salutations!

So I mainly programmed in Python and are relatively new to javascript. I'm currently trying to make a basic game to start to understand javascript. I only just stumbled across google scripts a few hours ago and I think it's really neat idea that allows for an easier time to develop web applications (which is seems Google is all about) having a GUI creation tool right along side is also a very nice feature.

But onto my problem. How do I actually move an image in javascript? I've found

      var obj = document.getElementById('IMG_Yellow_SW');
      obj.style.top = 50;
      obj.style.left = 50;
however I get a '"document" is not defined' error.