var topNav = {
    divisionOver : function(thisButtonId, isSelected){
        var thisButton = $(thisButtonId);
        var thisClass = thisButton.className;
        if(thisClass.indexOf("_selected") < 0 ){
            thisButton.className = "topnavSprite_" + thisButtonId + "_selected"; 
        }else{
            thisButton.parentNode.setAttribute("onmouseout", "topNav.divisionOut('" + thisButtonId + "', true);");
        }
    },
    divisionOut : function(thisButtonId, isSelected){
        if(!isSelected){
            $(thisButtonId).className = "topnavSprite_" + thisButtonId + "_notSelected"; 
        }
    }
};