var xmlhttp;

function envia(){
    var nome=document.getElementById('nome').value;
    var email=document.getElementById('emailtxt').value;
    xmlhttp=GetXmlHttpObject();
    if (xmlhttp==null){
        alert ("Your browser does not support AJAX!");
        return;
    }
    var url="index_form.php";
    url=url+"?nome="+nome+"&email="+email;
    xmlhttp.onreadystatechange=stateChanged;
    xmlhttp.open("GET",url,true);
    xmlhttp.send(null);
    return false;
}

function stateChanged(){
    if (xmlhttp.readyState==3){
        document.getElementById("box_03_conteudo").innerHTML='<img src=\"imgs/loader.gif\">';
    }
    if (xmlhttp.readyState==4){
        document.getElementById("box_03_conteudo").innerHTML=xmlhttp.responseText;
    }
}

function GetXmlHttpObject(){
    if (window.XMLHttpRequest){
        // code for IE7+, Firefox, Chrome, Opera, Safari
        return new XMLHttpRequest();
    }
    if (window.ActiveXObject){
        // code for IE6, IE5
        return new ActiveXObject("Microsoft.XMLHTTP");
    }
    return null;
}