var pushdown_height, box_height;
var img_height = 90;

window.onload = pushdown;

function pushdown() {
  if (!document.getElementsByTagName) return;

  var box = document.getElementById("box");
  var pushdown = document.getElementById("pushdown");

  // bail if box height can't be found
  if (!(box_height = getBoxHeight())) return;

  pushdown_height = (box_height - 2 - img_height);
  pushdown.style.height = (pushdown_height)+"px";
  pushdown.style.display = "block";
  
}

function getBoxHeight() {
  var maybe = (document.getElementById("heightHelper").offsetTop - 
	  document.getElementById("box").offsetTop);
  // sanity check;
  if (maybe > img_height) {
  	return maybe;
  }
  return false;
}