// JavaScript Document

 function GetXMLHttp() {  
     if(navigator.appName == "Microsoft Internet Explorer") {  
     xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");  
     } else {  
     xmlHttp = new XMLHttpRequest();  
     }      
     return xmlHttp;  
 }  
 var xmlRequest = GetXMLHttp();  

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