// stores the reference to the XMLHttpRequest object
var smsXmlHttp = smsCreateXmlHttpRequestObject(); 
// retrieves the XMLHttpRequest object
function smsCreateXmlHttpRequestObject() 
{	
  // will store the reference to the XMLHttpRequest object
  var xmlHttp;
  // if running Internet Explorer
  if(window.ActiveXObject)
  {
    try
    {
      xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");
    }
    catch (e) 
    {
      xmlHttp = false;
    }
  }
  // if running Mozilla or other browsers
  else
  {
    try 
    {
      xmlHttp = new XMLHttpRequest();
    }
    catch (e) 
    {
      xmlHttp = false;
    }
  }
  // return the created object or display an error message
  if (!xmlHttp)
    alert("Error creating the XMLHttpRequest object.");
  else 
    return xmlHttp;
}

function sendSMS() {
  if( smsXmlHttp.readyState == 4 || smsXmlHttp.readyState == 0 ) {
    var nr = document.getElementById('phonebox').value;
    var encodedText = encodeURIComponent(nr);
    document.getElementById('smsSendButton').focus();
    document.getElementById('phonebox').disabled = true;
    document.getElementById('smsSendButton').disabled = true;
    smsXmlHttp.open("GET", "/rpm_backend/sendsms.php?number="+encodedText, true);
    smsXmlHttp.onreadystatechange=handleSendSMSUpdate;
    smsXmlHttp.send(null);
  }
  return false;
}

function handleSendSMSUpdate() {
  if( smsXmlHttp.readyState == 4 && smsXmlHttp.status == 200 ) {
    var resp = smsXmlHttp.responseXML;
    var code, msg, nr;

    var elements = resp.documentElement.getElementsByTagName("code");
    if( elements.length > 0 ) {
      code = elements.item(0).firstChild.data;
    }
    
    elements = resp.documentElement.getElementsByTagName("msg");
    if( elements.length > 0 ) {
      msg = elements.item(0).firstChild.data;
    }
    
    elements = resp.documentElement.getElementsByTagName("nr");
    if( elements.length > 0 ) {
      nr = elements.item(0).firstChild.data;
    }
    
    //Show message
    document.getElementById("smsSenderMessage").innerHTML = msg;      
    document.getElementById('phonebox').disabled = false;
    document.getElementById('phonebox').focus();
    document.getElementById('smsSendButton').disabled = false;
    if( code == 0 ) { //All OK, set message-class to OK, empty box
      document.getElementById("smsSenderMessage").className = "smsSenderOKMsg";
      document.getElementById('phonebox').value="";      
    } else { //Nok OK.  
      //Re-enable textbox/button
      //Set message-class to error
      document.getElementById("smsSenderMessage").className = "smsSenderErrorMsg";
    }
  }
}