function showlayer1(layer){ 
document.getElementById('submeniu2').style.display="none"; 
document.getElementById('submeniu3').style.display="none";
document.getElementById('submeniu4').style.display="none"; 
if (document.getElementById(layer).style.display == "none"){
document.getElementById(layer).style.display="block"; 
} 
else { 
document.getElementById(layer).style.display="none"; 
}
}


function showlayer2(layer){
document.getElementById('submeniu1').style.display="none"; 
document.getElementById('submeniu3').style.display="none";
document.getElementById('submeniu4').style.display="none"; 
if (document.getElementById(layer).style.display == "none"){
document.getElementById(layer).style.display="block"; 
} 
else { 
document.getElementById(layer).style.display="none"; 
}
}

function showlayer3(layer){
document.getElementById('submeniu1').style.display="none"; 
document.getElementById('submeniu2').style.display="none";
document.getElementById('submeniu4').style.display="none"; 
if (document.getElementById(layer).style.display == "none"){
document.getElementById(layer).style.display="block"; 
} 
else { 
document.getElementById(layer).style.display="none"; 
}
}

function showlayer4(layer){
document.getElementById('submeniu1').style.display="none"; 
document.getElementById('submeniu2').style.display="none";
document.getElementById('submeniu3').style.display="none";
if (document.getElementById(layer).style.display == "none"){
document.getElementById(layer).style.display="block"; 
} 
else { 
document.getElementById(layer).style.display="none"; 
}
}