var topHtml;
function changeMenu(tID){
	if(topHtml == undefined){
		topHtml = document.getElementById("header").innerHTML;
	}

	if(tID == "top"){
		var tHtml = topHtml;
	}
	else{
		var tHtml = document.getElementById(tID).innerHTML;
	}
	
	document.getElementById("header").innerHTML = tHtml;
}