function layerVisivel(nome) {
    if (document.layers) {
        if (document[nome].display == "block")
            return true;
    } else if (document.all) {
        if (document.all[nome].style.display == "block")
            return true;
    } else if (document.getElementById) {
        if (document.getElementById(nome).style.display == "block") 
            return true;        
    }
    return false;
}  

function mostraLayer(nome) {
   if (document.layers)
       document[nome].display = "block";
   else if (document.all)
       document.all[nome].style.display = "block";
   else if (document.getElementById)
       document.getElementById(nome).style.display = "block";
}

function ocultaLayer(nome) {
    if (document.layers)
        document[nome].display = "none";
    else if (document.all)
        document.all[nome].style.display = "none";
    else if (document.getElementById)
        document.getElementById(nome).style.display = "none";
}

function mostraConteudo() {
  mostraLayer("conteudo");
}

function clickOnEnter(button, e) {
    var result = true;
    var keyCode = null;
    if (window.event) {
        keyCode = window.event.keyCode;
    } else if (e) {
        keyCode = e.which;
    }
    if (keyCode != null) {
        if (keyCode == 13) {
            if (window.event) {
                window.event.returnValue = false;
                window.event.cancel = true;
            }
            document.getElementById(button).click();
            result = false;
        }
    }
    return result;
}