var link = 1 // Hier het aantal linken invoeren.
var startfactor = 0 // Hier de startfactor invoeren, 0 = onzichtbaar.
var state = true

function SetVar(teller) {
a = teller
factor = startfactor
opac()
}

function opac() {

if(state){
factor++;if(factor == 100){clearTimeout(TimerId);}

if(document.all){
document.getElementById('venster1').style.visibility = "visible"
document.getElementById('venster1').style.filter =  "alpha(opacity="+factor+")" 
}
else{
document.getElementById('venster1').style.visibility = "visible"
document.getElementById('venster1').style.MozOpacity = (factor / 50)
}

TimerId = setTimeout("opac()",20)
state = false
}
else{
clearTimeout(TimerId)
for(i = 0; i < link;i++){
document.getElementById('venster1').style.visibility = "hidden"
}
state = true
opac()}
}