function RollIn(celda) { 
if (!celda.contains(event.fromElement)) {
celda.style.cursor = 'hand';
celda.bgColor ="#6699cc" ;
}
} 
function RollOut(celda) { 
if (!celda.contains(event.toElement)) {
celda.style.cursor = 'default';
celda.bgColor = "#666699";
}
}