function getRef(obj){
        return (typeof obj == "string") ?
        document.getElementById(obj) : obj;
}
function swapStyle(obj, style, value1, value2){
        obj= getRef(obj);
        // obj.isValue1 will be false the first time.
        if(!obj.isValue1){
                obj.style[style]= value1;
                obj.isValue1= true;
        }
        else{
                obj.style[style]= value2;
                obj.isValue1= false;
        }
}