var activeTab="tab1";

function resetLayers(){
	document.getElementById('layer1').style.visibility='hidden'; 
	document.getElementById('layer2').style.visibility='hidden'; 
	if(document.getElementById('layer3')){
			document.getElementById('layer3').style.visibility='hidden'; 
	}
	if(document.getElementById('layer4')){
		document.getElementById('layer4').style.visibility='hidden'; 
    }
	document.getElementById("tab1").className="tabNormal";
	document.getElementById("tab2").className="tabNormal";
	if(document.getElementById('tab3')){
		document.getElementById("tab3").className="tabNormal";
	}
	if(document.getElementById('tab4')){
		document.getElementById("tab4").className="tabNormal";	
	}
}

function selectTab(TabNr){
	resetLayers()
	activeTab="tab"+TabNr;
	document.getElementById("tab"+TabNr).className="tabRot";
	document.getElementById('layer'+TabNr).style.visibility='visible'; 
	
}