var aktiv =  false;
var isNAV =  false;
var isNAV6 = false;
var isIE =   false;

if(document.layers)         {aktiv=true; isNAV=true;}
if(document.all)            {aktiv=true; isIE=true;}
if(document.getElementById) {aktiv=true; isNAV6=true;}


function einblenden(tmpLayer) {
  if(isNAV) {
    document.layers[tmpLayer].visibility='show';
  }
  if(isNAV6) {
    document.getElementById(tmpLayer).style.visibility='visible';
  }
  if(isIE) {
    document.all[tmpLayer].style.visibility='visible';
  }
}


function ausblenden() {
  if(isNAV) {
	var anzahl_layer = 4;
    for (var i=0; i<anzahl_layer+1; i++){
      document.layers['UM'+i].visibility='hide'
	}
  }
  if(isNAV6) {
	var anzahl_layer = 4;
    for (var i=0; i<anzahl_layer+1; i++){
      document.getElementById('UM'+i).style.visibility='hidden'
	}
  }
  if(isIE) {
	var anzahl_layer = 4;
    for (var i=0; i<anzahl_layer+1; i++){
      document.all['UM'+i].style.visibility='hidden'
	}
  }
}