function checkNameExists(input, response)
{
  if (response != ''){ 
    // Response mode
    message   = document.getElementById('nameCheckFailed');
    if (response == '1'){
      message.className = 'error';
    }else{
      message.className = 'hidden';
    } 
  }else{
    // Input mode
    url  = 'http://public.cerbumi.org/ajax_available?username=' + input;
    loadXMLDoc(url);
  }
}

function checkEmailExists(input, response)
{
  if (response != ''){ 
    // Response mode
    message   = document.getElementById('emailCheckFailed');
    if (response == '1'){
      message.className = 'error';
    }else{
      message.className = 'hidden';
    } 
  }else{
    // Input mode
    url  = 'http://public.cerbumi.org/ajax_emailavailable?email=' + input;
    loadXMLDoc(url);
  }
}

function processReqChange() 
{
    // only if req shows "complete"
    if (req.readyState == 4) {
        // only if "OK"
        if (req.status == 200) {
            // ...processing statements go here...
      response  = req.responseXML.documentElement;

      method    =
response.getElementsByTagName('method')[0].firstChild.data;

      result    = 
response.getElementsByTagName('result')[0].firstChild.data;

      eval(method + '(\'\', result)');
        } else {
            alert("There was a problem retrieving the XML data:\n" + req.statusText);
        }
    }
}

function loadXMLDoc(url) 
{
    // branch for native XMLHttpRequest object
    if (window.XMLHttpRequest) {
        req = new XMLHttpRequest();
        req.onreadystatechange = processReqChange;
        req.open("GET", url, true);
        req.send(null);
    // branch for IE/Windows ActiveX version
    } else if (window.ActiveXObject) {
        req = new ActiveXObject("Microsoft.XMLHTTP");
        if (req) {
            req.onreadystatechange = processReqChange;
            req.open("GET", url, true);
            req.send();
        }
    }
}