function amostra(idDiv) {

    if(document.layers) {
        document.layers[idDiv].visibility = true;
    }
    if(document.all) {
        document.all(idDiv).style.visibility = 'visible';
    }
    if(document.getElementById) {
        document.getElementById(idDiv).style.visibility = 'visible';
    }
}

function esconde(idDiv) {
    if(document.layers) {
        document.layers[idDiv].visibility = false;
    }
    if(document.all) {
        document.all(idDiv).style.visibility = 'hidden';
    }
    if(document.getElementById) {
        document.getElementById(idDiv).style.visibility = 'hidden';
    }
}