function rollOver(e){    
    obj = e.src;
    
    if(obj.search('_active') > -1){
        newURL = obj.replace('_active.jpg','.jpg');
        document.getElementById(e.id).src = newURL;
    }else{
        newURL = obj.replace('.jpg','_active.jpg');
        document.getElementById(e.id).src = newURL;
    }
}