var currentHeader = -1;
window.setInterval("changePageHeader()", 5000);

function changePageHeader()
{
	var i = Math.round( Math.random() * 3 ) + 1;
	while (i == currentHeader)
	{
		i = Math.round( Math.random() * 3 ) + 1;
	}
	document.getElementById("pageHeader").src = "/Images/Header" + i + ".jpg";
	document.getElementById("pageHeader").style.visibility = "visible";
}

window.onload = function(){changePageHeader();}

function showPopup( url )
{
	window.showModalDialog( url, null, "dialogHeight: 902px; dialogWidth:500px; scroll: yes;" );
}