onload = function() {

	isNumeric = function(sText)
	{
	   var ValidChars = "0123456789.";
	   var IsNumber=true;
	   var Char;

	 
	   for (i = 0; i < sText.length && IsNumber == true; i++) 
		  { 
		  Char = sText.charAt(i); 
		  if (ValidChars.indexOf(Char) == -1) 
			 {
			 IsNumber = false;
			 }
		  }
	   return IsNumber;
	   
	}
	

  // Mouseover-Effekt für die Navigation
  var images = document.getElementById("top").getElementsByTagName("img");
  
  for (image in images) {
	   if(isNumeric(image) || image.search(/nav_/) >= 0)
	   {
		   if(images[image].src.search(/_hover.gif/) < 0)
		   {
			   images[image].onmouseover = function() {
					newImage = new Image();
					newImage.src = "/images/nav/"+this.id+"_hover.gif";
					
					document.getElementById(this.id).src = newImage.src;
			   }
			   
			   images[image].onmouseout = function() {
					newImage = new Image();
					newImage.src = "/images/nav/"+this.id+".gif";
					
					document.getElementById(this.id).src = newImage.src;
			   }
		   }
	   }
  }
  
}