function position() {
  if (navigator.userAgent.match(/7\.0/i)) {
    hoehe=(document.body.clientHeight-480)/2;
  }
  else if (navigator.userAgent.match(/msie 6\.0/i)) {
    hoehe=(document.body.clientHeight-598)/2;
  }
  else if (navigator.userAgent.match(/opera/i)) {
    hoehe=(document.body.clientHeight-380)/2;
  }
  else {
    hoehe=(document.body.clientHeight-520)/2;
  }
  if (hoehe>0) { document.getElementById('container').style.marginTop=hoehe+'px'; }
}

function bild_on(oben,links,bild) {
  document.getElementById('pic').style.visibility='visible';
  document.getElementById('pic').style.margin=oben+'px 0px 0px '+links+'px';
  document.getElementById('pic').src=bild;
}

function bild_out() {
  document.getElementById('pic').style.visibility='hidden';
}