iframe 높이 자동 리사이징

html 소스

<iframe width="700" id="the_iframe" onload="calcHeight();" src="testing_page.shtml" scrolling="NO" frameborder="1" height="1"></iframe>

javascript 소스

function calcHeight()
{
  //find the height of the internal page
  var the_height = document.getElementById('the_iframe').contentWindow.document.body.scrollHeight;

  //change the height of the iframe
  document.getElementById('the_iframe').height = the_height;
}