function Tab(pid,mid,onof,ovr) {

	lf = document.getElementById("lf"+pid);
	rt = document.getElementById("rt"+pid);
	tb = document.getElementById("tab"+pid);
	if(ovr=="over") {
		lf.src = "/pics/tb_lf_on.gif";
		rt.src = "/pics/tb_rt_on.gif";
		tb.style.backgroundImage="url('/pics/tb_on.gif')";
	} else {
		lf.src = "/pics/tb_lf_"+onof+".gif";
		rt.src = "/pics/tb_rt_"+onof+".gif";
		if(onof=='on') {
			tb.style.backgroundImage="url('/pics/tb_on.gif')";
		} else {
			tb.style.backgroundImage="url('/pics/tb_of.gif')";
		}
		div = document.getElementById('sidenav');
		div.innerHTML='';
		pid = mid;
		return true;
	}

	var http = null;
	var newDate = new Date;
	var url = "/sidenav.htm?nc="+newDate.getTime()+"&pid="+pid;
	try { http=new XMLHttpRequest(); }
	catch (e) { try { http=new ActiveXObject("Msxml2.XMLHTTP"); }
	catch (e) { http=new ActiveXObject("Microsoft.XMLHTTP"); } }
	if (http==null) { alert ("Your browser does not support AJAX!"); return; }
	http.open("GET",url,true);
	http.onreadystatechange = function() {
		if(http.readyState==4) {
			div = document.getElementById('sidenav');
			div.innerHTML = http.responseText;
		}
	}
	http.send(null);
}