[Deff]

TypeError: document.getElementByID is not a function
document.getElementByID('frame1').src="source.html ?"+(+new Date())

Пробуйте так

<script type="text/javascript">
 function refreshIFrame(sel) {
   setTimeout(function(){sel.src="source.html?"+(+new Date());},2000);
}
 </script>
<iframe src="source.html" name="MainFrame" height="100" width="100" frameborder="0" scrolling="no" onload="refreshIFrame(this)"> </iframe>