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