function changeArea (a,b)  {
	for (i=1;i<=b;i++) {
		var oh = document.getElementById("area"+i);
		var ohbtn = document.getElementById("tab"+i);	
		//os.style.display = "none";
		oh.className = "disn";
		ohbtn.className = "";
		}
	var os = document.getElementById("area"+a);
	os.className = "disb";
	var osbtn = document.getElementById("tab"+a);
	osbtn.className = "current";	
	}