function mouseOver(n) {
switch (n)
{
case 1:
  document.getElementById('projecttitel1').style.background="url(../img/balkblauw.jpg) no-repeat 0px 100px;";
  break;
case 2:
  document.getElementById('projecttitel2').style.background="url(../img/balkblauw.jpg) no-repeat 0px 100px;";
  break;
case 3:
  document.getElementById('projecttitel3').style.background="url(../img/balkblauw.jpg) no-repeat 0px 100px;";
  break;
case 4:
  document.getElementById('projecttitel4').style.background="url(../img/balkblauw.jpg) no-repeat 0px 100px;";
  break;
case 5:
  document.getElementById('projecttitel5').style.background="url(../img/balkblauw.jpg) no-repeat 0px 100px;";
  break;
case 6:
  document.getElementById('projecttitel6').style.background="url(../img/balkblauw.jpg) no-repeat 0px 100px;";
  break;
case 7:
   document.getElementById('projecttitel7').style.background="url(../img/balkblauw.jpg) no-repeat 0px 100px;";
   break;
case 8:
   document.getElementById('projecttitel8').style.background="url(../img/balkblauw.jpg) no-repeat 0px 100px;";
   break;
case 9:
  document.getElementById('projecttitel9').style.background="url(../img/balkblauw.jpg) no-repeat 0px 100px;";
  break;
case 10:
  document.getElementById('projecttitel10').style.background="url(../img/balkblauw.jpg) no-repeat 0px 100px;";
  break;
case 11:
   document.getElementById('projecttitel1').style.background="url(../img/balkblauw.jpg) no-repeat 0px 100px;";
   break;
case 12:
   document.getElementById('projecttitel2').style.background="url(../img/balkblauw.jpg) no-repeat 0px 100px;";
   break;
case 20:
  document.getElementById('projecttite20').style.background="url(../img/balkblauw.jpg) no-repeat 0px 100px;";
  break;
case 21:
  document.getElementById('projecttitel21').style.background="url(../img/balkblauw.jpg) no-repeat 0px 100px;";
  break;
case 22:
  document.getElementById('projecttitel22').style.background="url(../img/balkblauw.jpg) no-repeat 0px 100px;";
  break;
case 23:
  document.getElementById('projecttitel23').style.background="url(../img/balkblauw.jpg) no-repeat 0px 100px;";
  break;
case 24:
  document.getElementById('projecttitel24').style.background="url(../img/balkblauw.jpg) no-repeat 0px 100px;";
  break;
case 25:
  document.getElementById('projecttitel25').style.background="url(../img/balkblauw.jpg) no-repeat 0px 100px;";
  break;
case 26:
   document.getElementById('projecttitel26').style.background="url(../img/balkblauw.jpg) no-repeat 0px 100px;";
   break;
case 27:
   document.getElementById('projecttitel27').style.background="url(../img/balkblauw.jpg) no-repeat 0px 100px;";
   break;
case 28:
  document.getElementById('projecttitel28').style.background="url(../img/balkblauw.jpg) no-repeat 0px 100px;";
  break;
default: break;}
}