function ajax(url, target, msg) {
        
        document.getElementById(target).innerHTML = msg;
        
        //native XMLHttpRequest object
        if (window.XMLHttpRequest) {
        req = new XMLHttpRequest();
        req.onreadystatechange = function() {ajaxDone(target);};
        req.open("GET", url, true);
        req.send(null);
        
        //IE/Windows Activex version
        } else if (window.ActiveXObject) {
            
            req = new ActiveXObject("Microsoft.XMLHTTP");
            
            if (req) {
                req.onreadystatechange = function() {ajaxDone(target);};
                req.open("GET", url, true);
                req.send();
            }
      }
}


function ajaxDone(target) {
    
    //only if red is "loaded"
    if (req.readyState == 4) {
    
            //only if "OK"
            if (req.status == 200) {
                results = req.responseText;
                document.getElementById(target).innerHTML = results;
                }else {
                    document.getElementById(target).innerHTML = "Problemas! (" + req.statusText + "). Contacte o administrador";
                    }
          }
}