function elem(name) {
  return document.getElementById(name);
}

function imgpreload() {
  elem("loading").innerHTML='<img src="images/holding/loading.gif" width="16" height="16" />';
  preload("immo.jpg");
  preload("steuer.jpg");
  preload("apo.jpg");
  preload("finanz.jpg");
  preload("unternehmen.jpg");
  elem("loading").innerHTML='';
}

function preload(img) {
  loader=new Image(); 
  loader.src="images/holding/"+img;
}

function showimg(img) {
  elem("content").style.backgroundImage='url(images/holding/'+img+')';
}

function hideimg() {
  elem("content").style.backgroundImage='url(images/holding/bg_bildmarke.gif)';
}