var currentMenu = null;

if (!document.getElementById)
    document.getElementById = function() { return null; }

function showImage(image) {
	image.defaultsrc = image.src;
	index = image.src.indexOf(".jpg");
	image.src = image.src.substring(0,index)+"_over.jpg"
}

function hideImage(image) {
	image.src = image.defaultsrc;
}

function initializeMenu(menuId, actuatorId, imageId) {
	var menu = document.getElementById(menuId);
	var actuator = document.getElementById(actuatorId);
	var image = document.getElementById(imageId);

	
	if (actuator == null) return;
	
	actuator.onmouseover = function() {
		if (currentMenu == null) {
	  	this.showMenu();
	  } else {
    	currentMenu.style.visibility = "hidden";
	    currentMenu = null;
	    this.showMenu();
	  }
	}
	
	actuator.onmouseout = function() {
		if (currentMenu != null) {
	  	currentMenu.style.visibility = "hidden";
	    currentMenu = null;
	  }
		if (image!=null)
			image.style.visibility = "hidden";
	}
	
	if (menu!=null) {
		menu.onmouseout = function() {
			if (currentMenu != null) {
		  	currentMenu.style.visibility = "hidden";
		    currentMenu = null;
		  }
			if (image!=null)
				image.style.visibility = "hidden";
		}
	}
	
	actuator.showMenu = function() {
		if (menu!=null) {
			menu.style.left = this.getRealLeft()-1+"px";
			menu.style.top = this.getRealTop() + this.offsetHeight + "px";
			menu.style.visibility = "visible";
			currentMenu = menu;
		}
		if (image!=null) {
			image.style.left = this.getRealLeft()+"px";
			image.style.top = this.getRealTop() + "px";
			image.style.visibility = "visible";
		}
	}
	
	actuator.getRealLeft = function() {
    xPos = this.offsetLeft;
    tempEl = this.offsetParent;
    while (tempEl != null) {
        xPos += tempEl.offsetLeft;
        tempEl = tempEl.offsetParent;
    }
    return xPos;
	}
	
	actuator.getRealTop = function() {
    xPos = this.offsetTop;
    tempEl = this.offsetParent;
    while (tempEl != null) {
        xPos += tempEl.offsetTop;
        tempEl = tempEl.offsetParent;
    }
    return xPos;
	}
}