function Image_Swap(daImage, daImg){
	var objStr;
	var obj;
	if(document.images){
	        if (typeof(daImage) == 'string') {
	                objStr = 'document.' + daImage;
	                obj = eval(objStr);
	                obj.src = daImg.src;
	        } else if ((typeof(daImage) == 'object') && daImage && daImage.src) {
	                daImage.src = daImg.src;
	        }
	}
}  
var menu_on = new Image(24,19);
menu_on.src = 'images/menu_on.gif';
var menu_off = new Image(24,19);
menu_off.src = 'images/menu_off.gif';
var menu_roll = new Image(24,19);
menu_roll.src = 'images/menu_roll.gif';