var isNav = (navigator.appName == "Netscape");
var topAdjust = 10;
var menuImgLeft = new Array();
var menuImgTop = new Array();
var imageHeight = 34;// the Height of topMenu Images

function menuPosition(){
	for (var i = 0; i < 4; i++){
		var menuID = "dropDownMenu_" + parseInt(i + 1);
		var imageID = "topMenuImg_" + parseInt(i + 1);
		var menu = document.getElementById(menuID);
		var menuImage = document.getElementById(imageID);
		var menuImagePos = getElementPosition(imageID);
		var menuLeft = menuImagePos.left;
		var menuTop = menuImagePos.top;
		
		
		menuImgLeft[i] = parseInt(menuImagePos.left);
		menuImgTop[i] = parseInt(menuImagePos.top);
		
		menu.style.left = parseInt(menuLeft) + "px";
		menu.style.top = parseInt(menuTop) + parseInt(imageHeight) + topAdjust + "px";
		
		// Creating background for menus
		var menuBG = document.createElement("div");
		menuBG.className = "menuBackground";
		menuBG.id = "menuBG_" + i;
		var menuBGHeight = menu.offsetHeight;
		menuBG.style.height = parseInt(menuBGHeight) + "px";
		menuBG.style.left = menu.style.left;
		menuBG.style.top = menu.style.top;
		
		document.body.appendChild(menuBG);
	}
	//alert(document.getElementById('dropDownMenu_2').offsetHeight);
	
}
var timer;

function getElementPosition(elemID){
	var offsetTrail = document.getElementById(elemID);
	var offsetLeft = 0;
	var offsetTop = 0;
	while(offsetTrail){
		offsetLeft += offsetTrail.offsetLeft;
		offsetTop += offsetTrail.offsetTop;
		offsetTrail = offsetTrail.offsetParent;
	}
	return {left:offsetLeft, top:offsetTop};
}

function keepMenu() {
    clearTimeout(timer);
}

function requestHide() {
    timer = setTimeout("hideMenus()", 250);
}

function hideMenus() {
    for (var i = 0; i < 4; i++) {
		// Hiding Menus
      var menuID = "dropDownMenu_" + parseInt(i + 1);
	  var menu = document.getElementById(menuID);
      menu.style.visibility = "hidden";
	  // Hiding Backgrounds
	  var bgID = "menuBG_" + i;
	  var menuBackground = document.getElementById(bgID);
	  menuBackground.style.visibility = "hidden"; 
    }
}

function showMenu(menuId) {
    
        keepMenu();
        hideMenus();
       
        var menu = document.getElementById(menuId);
        menu.style.visibility = "visible";
		// Displaying Background
		var bgIndex = parseInt(menuId.charAt(13)) - 1;
		var bgID = "menuBG_" + bgIndex;
		var menuBG = document.getElementById(bgID);
    	menuBG.style.visibility = "visible";
}

function swap(evt) {
    evt = (evt) ? evt : ((event) ? event : null);
   
        if (evt && (document.getElementById && document.styleSheets)) {
            var elem = (evt.target) ? evt.target : evt.srcElement;
			
            if (elem.id.indexOf("topMenuImg") != -1) {
                if (evt.type == "mouseover") {
					var index = elem.id.charAt(11);
					var menuID = "dropDownMenu_" + parseInt(index);
                    showMenu(menuID);
                    
                } else if (evt.type == "mouseout") {
                    requestHide();
                }
                evt.cancelBubble = true;
            }
        }
   
}