function klappmenu(menulink)
{ 
var zaehl = 'w' + 0;
var GECKO = document.getElementById? 1:0 ;
var NS = document.layers? 1:0 ;
var IE = document.all? 1:0 ;
if (GECKO) {
document.getElementById(menulink).style.display= (document.getElementById(menulink).style.display=='block') ? 'none' : 'block';
for(var i = 0; i <= 5; i++) {
var pruef = 'u' + i; 
if(menulink != pruef) { 
document.getElementById(pruef).style.display = 'none'; 
document.getElementById(zaehl).style.display = 'none'; 
} 
} 
} 
else if (NS) {
document.layers[menulink].display=(document.layers[menulink].display== 'block') ? 'none' : 'block';
for(var i = 0; i <= 5; i++) {
var pruef = 'u' + i; 
if(menulink != pruef) { 
document.layers[pruef].display = 'none'; 
document.layers[zaehl].display = 'none'; 
} 
} 
} 
else if (IE) {
document.all[menulink].style.display=(document.all[menulink].style.display== 'block') ? 'none' : 'block';
for(var i = 0; i <= 5; i++) {
var pruef = 'u' + i; 
if(menulink != pruef) { 
document.all[pruef].style.display = 'none'; 
document.all[zaehl].style.display = 'none'; 
} 
} 
}
}