document.onload = load();

function load() 
{
  preloader();
}

function preloader() 
{
  // counter
  var i = 0;
  
  // create object
  imageObj = new Image();
  
  // set image list
  images = new Array();
  images[0]="images/header_btn_dine_over.gif"
  images[1]="images/header_btn_spa_over.gif"
  images[2]="images/header_btn_stay_over.gif"
  
  // start preloading
  for(i=0; i<=3; i++) 
  {
      imageObj.src=images[i];
  }
}