function popitUp1(url) 
{
window.open('visitekaartjes/bert.html', 'bert',  ' width=275,height=150,');
}
function popitUp2(url) 
{
window.open('visitekaartjes/pieter.html', 'pieter',  ' width=275,height=150,');
}
function popitUp3(url) 
{
window.open('visitekaartjes/arjan.html', 'arjan',  ' width=275,height=150,');
}
function popitUp4(url) 
{
window.open('visitekaartjes/maaike.html', 'maaike',  ' width=275,height=150,');
}
function popitUp5(url) 
{
window.open('visitekaartjes/riek.html', 'riek',  ' width=275,height=150,');
}
function popitUp6(url) 
{
window.open('visitekaartjes/erwin.html', 'erwin',  ' width=275,height=150,');
}