// Quick check for support for DOM
//var W3CDOM = (document.createElement && document.getElementsByTagName);
var W3CDOM = true;

// Collections of images -- hover and off
var navbarOverImgs = new Array ();
var navbarOutImgs = new Array();

/**
 * Onload event for page!
 */
window.onload = function() {

  // Establish rollover hook for navigation elements
  hookRolloversForNavImages();
  
}

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/**
 * Sets up the events for navigation link hovers...
 */
 function hookRolloversForNavImages() {
 
   // No rollovers if don't support DOM
   if (!W3CDOM) return;
   
   var imgs = document.getElementsByTagName('img');
      
   for (var i=0; i < imgs.length; i++) {
   
    var className = imgs[i].className;
    
    // If not a thumbnail, next image
    if (className != 'thumbnail')
      continue;
   
     // Call function whenever mouse goes over
	  imgs[i].onmouseover = navbarOver;
	  
	  // Call function whenever mouse goes out
		imgs[i].onmouseout = navbarOut;
   
    // Rollovers have the form !name.gif
		navbarOutImgs[i] = new Image();
		navbarOutImgs[i].src = imgs[i].src;
		navbarOverImgs[i] = new Image();
		navbarOverImgs[i].src = imgs[i].src.substring(0,imgs[i].src.indexOf('-off')) +"-hover"+ imgs[i].src.substring(imgs[i].src.lastIndexOf('.'));
		imgs[i].number = i;
   }
 }

// Changes source of images on a rollover
function navbarOver () {
  this.src = navbarOverImgs[this.number].src;
}

// Changes source of images on a rollout
function navbarOut () {
  this.src = navbarOutImgs[this.number].src;
}

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