function abrirPag(valor){var url = valor;
xmlRequest.onreadystatechange = mudancaEstado;xmlRequest.open("GET",url,true);xmlRequest.send(null);
if (xmlRequest.readyState == 1) {document.getElementById("conteudo_mostrar").innerHTML = "<img src='img/carregando.gif'>";}
return url;}
function mudancaEstado(){if (xmlRequest.readyState == 4){document.getElementById("conteudo_mostrar").innerHTML = xmlRequest.responseText;}}