// JavaScript Document
function ObjAjax(){
  try{return new XMLHttpRequest()}
  catch(e){try{return new ActiveXObject("Msxml2.XMLHTTP")}
  catch(e){return new ActiveXObject("Microsoft.XMLHTTP")}}
  return null;
}

function navegar(page){
  ajax = new ObjAjax();
  var div = document.getElementById("conteudo");

  ajax.onreadystatechange = function(){
    if(ajax.readyState == 1){div.innerHTML="Carregando...";}
    if(ajax.readyState == 4){div.innerHTML=ajax.responseText;}

  }
  ajax.open("GET",page,true);
  ajax.send(null);
}