var http_request;
var obj;
var tpBrowser;

if(window.XMLHttpRequest){
tpBrowser='ns';
http_request = new XMLHttpRequest();
    if(http_request.overrideMimeType)
    http_request.overrideMimeType('text/xml');
}

if(window.ActiveXObject){
tpBrowser='ie';
try {http_request=new ActiveXObject("Msxml2.XMLHTTP");}
catch (e){
    try{http_request=new ActiveXObject("Microsoft.XMLHTTP");}
    catch(e){}
    }
}

function obterRequisicao( pagina ,elemento){
    obj = document.getElementById(elemento);

    if(http_request==null){
    alert('Nãi foi possivel instanciar XMLHTTPREquest.');
    return false;
    }

    http_request.onreadystatechange = mostrarConteudo;
    http_request.open('GET',pagina,true);
    http_request.send(null);

}

function mostrarConteudo(){
    if(http_request.readyState == 4){

        if(http_request.status == 0)      {

            var xmldoc = http_request.responseXML;
            var no=xmldoc.getElementsByTagName('Arenas').item(0);
            var valor=no.firstChild.data;

            if(tpBrowser=='ns')obj.textContent= valor;
            else if (tpBrowser=='ie') obj.innerText= valor;
        }
        else alert('Falha ao fazer requisição de dados.');
    }