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 = "<table width=310 height=150><tr><td><img src='img/carregando.gif'></td></tr></table>";
	
	}
	return 
	url;

}

function mudancaEstado(){
	if (xmlRequest.readyState == 4){document.getElementById("conteudo_mostrar").innerHTML = xmlRequest.responseText;
	}
}