var hover = {

   isSelected : null,
   theImgs : null,
   theLIs : null,
   imgOff : [], 
   imgOver : [],

   init : function(){
	
		var theNav = document.getElementById('top_nav');
		if(theNav){
			hover.theImgs = theNav.getElementsByTagName('img');

			for (var i=0; i < 6; i++){
				hover.imgOff[i] = new Image();
				hover.imgOff[i].src = hover.theImgs[i].src;
				hover.imgOver[i] = new Image();
				//if(i != 1){	
					hover.imgOver[i].src = hover.theImgs[i].src.substring(0, hover.theImgs[i].src.lastIndexOf('.')) + '_selected' + '.png';
					hover.theImgs[i].number = i;
				//}
			}
      
			//hover.imgOver[1].src = '/images/common/Top_Nav_2_Hover.png';
			
			hover.isSelected = false;
    		//var tn2 = document.getElementById("tn2");
    		var topNav = document.getElementById('top_nav');
			hover.theLIs = topNav.getElementsByTagName('li');
			var theImg = hover.theLIs[1].getElementsByTagName('img')[0];
			if(theImg.src.search("_selected") != -1){hover.isSelected = true;}
			
			/*
			tn2.onmouseover = hover.showDropdown;
			tn2.onmouseout = hover.hideDropdown;
		  */
		
   			if (typeof document.body.style.maxHeight === "undefined") {//if IE 6
				hover.fixie6png();

			}
			else{
				hover.addEvent(hover.theImgs[0], 'mouseover', hover.navOver);
				hover.addEvent(hover.theImgs[0], 'mouseout', hover.navOff);
				
				for (var i=1; i<hover.theLIs.length; i++){
					hover.addEvent(hover.theImgs[i], 'mouseover', hover.navOver);
					hover.addEvent(hover.theImgs[i], 'mouseout', hover.navOff);
				}
			}
		}
  },  
  
  showDropdown : function(){
	var theImg = this.getElementsByTagName('img')[0];
	var theSource = theImg.src;
	this.className = "over";
	if (typeof document.body.style.maxHeight === "undefined") {
		theImg.style.filter = "progid:DXImageTransform.Microsoft.AlphaImageLoader(src='"+hover.imgOver[1].src +"', sizing='scale')"; 
	}
	else{theImg.src = hover.imgOver[1].src;}
  },
  
  hideDropdown : function(){
	var theImg = this.getElementsByTagName('img')[0];
	this.className = "";
	if (typeof document.body.style.maxHeight === "undefined" && hover.isSelected == false) {
		theImg.style.filter = "progid:DXImageTransform.Microsoft.AlphaImageLoader(src='"+hover.imgOff[1].src+"', sizing='scale')"; 
	}
	/*
	else if(typeof document.body.style.maxHeight === "undefined" && hover.isSelected == true){
		theImg.style.filter = "progid:DXImageTransform.Microsoft.AlphaImageLoader(src='images/common/Top_Nav_2_selected.png', sizing='scale')"; 
	}
	*/
	else{
	  /*
		if(hover.isSelected == true){
			theImg.src =  'images/common/Top_Nav_2_selected.png';
		}
		else{
		*/
			theImg.src = hover.imgOff[1].src;
		//}
	}
  },
  
  navOver : function (){
	var theSource = this.src;
	if(theSource.search('_selected') == -1){
		hover.theImgs[this.number].src = hover.imgOver[this.number].src;
	}
  },
  
  navOff : function(){
	var theSource = this.src;
	hover.theImgs[this.number].src = hover.imgOff[this.number].src;
  },
  
  tnHover : function(){
	var theFilter = this.style.filter;
	if(theFilter.search('_selected') == -1){
		this.style.filter = "progid:DXImageTransform.Microsoft.AlphaImageLoader(src='"+hover.imgOver[this.number].src+"', sizing='scale')"; 
	}
  },
  
  tnOff : function(){
	var theFilter = this.style.filter;
	this.style.filter = "progid:DXImageTransform.Microsoft.AlphaImageLoader(src='"+hover.imgOff[this.number].src+"', sizing='scale')";
  },
 
  fixie6png : function() {
	for(var i=0; i<=hover.theLIs.length; i++){
		var tnImage = document.getElementById("tn" + i + "_img");
		if(tnImage){
			var imageSource = tnImage.src;
			tnImage.src = "/images/common/blank.gif";
			tnImage.style.filter = "progid:DXImageTransform.Microsoft.AlphaImageLoader(src='" + imageSource + "', sizing='scale')";
		}
	}
	
	for (var i=2; i<hover.theLIs.length; i++){
		hover.addEvent(hover.theImgs[i], 'mouseover', hover.tnHover);
		hover.addEvent(hover.theImgs[i], 'mouseout', hover.tnOff);
	}
	
	hover.addEvent(hover.theImgs[0], 'mouseover', hover.tnHover);
	hover.addEvent(hover.theImgs[0], 'mouseout', hover.tnOff);
	
  },

  addEvent : function(obj, type, func) {
    if (obj.addEventListener) {obj.addEventListener(type, func, false);}
    else if (obj.attachEvent) {
      obj["e" + type + func] = func;
      obj[type + func] = function() {obj["e" + type + func] (window.event);}
      obj.attachEvent("on" + type, obj[type + func]);
    }
    else {obj["on" + type] = func;}
  }
}

hover.addEvent(window, 'load', hover.init);