function popup(menu){
if(menu==1){document.getElementById('popdreh').style.visibility='visible';document.getElementById('popdreh2').style.visibility='visible';document.getElementById('popdreh3').style.visibility='visible';}
if(menu==2){document.getElementById('popfraes').style.visibility='visible';document.getElementById('popfraes2').style.visibility='visible';document.getElementById('popfraes3').style.visibility='visible';document.getElementById('popfraes4').style.visibility='visible';}
if(menu==3){document.getElementById('popschleif').style.visibility='visible';document.getElementById('popschleif2').style.visibility='visible';}
if(menu==4){document.getElementById('poptrans').style.visibility='visible';document.getElementById('poptrans2').style.visibility='visible';document.getElementById('poptrans3').style.visibility='visible';}
}
function popdown(menu){
if(menu==1){document.getElementById('popdreh').style.visibility='hidden';document.getElementById('popdreh2').style.visibility='hidden';document.getElementById('popdreh3').style.visibility='hidden';}
if(menu==2){document.getElementById('popfraes').style.visibility='hidden';document.getElementById('popfraes2').style.visibility='hidden';document.getElementById('popfraes3').style.visibility='hidden';document.getElementById('popfraes4').style.visibility='hidden';}
if(menu==3){document.getElementById('popschleif').style.visibility='hidden';document.getElementById('popschleif2').style.visibility='hidden';}
if(menu==4){document.getElementById('poptrans').style.visibility='hidden';document.getElementById('poptrans2').style.visibility='hidden';document.getElementById('poptrans3').style.visibility='hidden';}
}

var sichtbar=0;
function timer(){
if(sichtbar<98){
window.setTimeout('weiter()','100');}else {timer2();}
}
function timer2(){
if(sichtbar>2){
window.setTimeout('weiter2()','100');}
}
function weiter(){
sichtbar=sichtbar+2;
document.getElementById('fade').style.filter="Alpha(opacity="+sichtbar+")";
document.getElementById('fade').style.MozOpacity=sichtbar/100;
timer();
}
function weiter2(){
sichtbar=sichtbar-2;
document.getElementById('fade').style.filter="Alpha(opacity="+sichtbar+")";
document.getElementById('fade').style.MozOpacity=sichtbar/100;
timer2();
}