function showCosts()
	{
		var vheight = Screen.getViewportHeight();
		var vpos = Math.floor((vheight - 400) / 2);
		if (vpos < 50) vpos = 50;
		document.getElementById("purchase_comparison_inner").style.top = (Screen.getScrollTop() + vpos) + "px";
		document.getElementById("purchase_comparison").className = "ie6bghack";
	       document.getElementById("purchase_comparison").style.display = 'block';
	       document.getElementById("purchase_comparison").style.height = Screen.getDocumentHeight() + "px";
	}

	function hideCosts()
	{
		document.getElementById("purchase_comparison").style.display = "none";
	}