function showorhide1(f){
if(f){visi="visible";
hid="hidden";}
else{visi="hidden";
hid="visible";}
if(document.layers){
document.laag1.visibility=visi;
document.laag2.visibility=hid;
}
if(document.all){
document.all.laag1.style.visibility=visi;
document.all.laag2.style.visibility=hid;
}
if(document.getElementById){
document.getElementById("laag1").style.visibility=visi;
document.getElementById("laag2").style.visibility=hid;
}
}