var oBody;

window.onload = fnLoad;

function fnLoad()
{
     oBody = document.body;
	 window.onresize = fnToggleSize;
     fnToggleSize();
}

function fnToggleSize()
{
	var sClassCurrent = oBody.className;
	var sClassNew = null;
	var i = document.body.clientWidth;

	if (i >= 612)
		{
		sClassNew = "640";

		//toggle for Adstamp
		if (document.body.all.adstamp)
			{
				document.body.all.adstamp.children(0).style.display = "none"
			}

		}

	
	if (i >= 772)
	{
		sClassNew = "800";

		//toggle for Adstamp
		if (document.body.all.adstamp)
			{
				document.body.all.adstamp.children(0).style.display = "block"
			}

	}

	if (sClassNew !== null && sClassNew !== sClassCurrent) {oBody.className = sClassNew;}
}