function wrong_mail_address(adresa){
  var re = /^[_a-zA-Z0-9\.\-]+@[_a-zA-Z0-9\.\-]+\.[a-zA-Z]{2,4}$/;
  return re.test(adresa) == 0;
}

function objGet(id){
   if(Boolean(document.getElementById))
      return document.getElementById(id);
   else if(Boolean(document.all))
      return eval('document.all.'+id);
   else
      return eval('document.'+id);
}


//-----------------------------------------------------------------------------
// kontrola formulare (inputy oznacene rel="required")

var styleNormal='btn';
var styleDisabled='btn-dis';

function validateForm(form, relValue){
  var submit;
  var dis=false;
  var inputs = form.getElementsByTagName('input');
  for(var i=0; i < inputs.length; i++) {
    if(inputs[i].type=='submit') submit=inputs[i];
    if(inputs[i].getAttribute('rel')==relValue){
      if(inputs[i].value==''){
        dis=true;
      }
    } 
  }
  
  submit.disabled=dis;
  if(dis) 
    submit.className=styleDisabled;
  else
    submit.className=styleNormal;
}


function send_xmlhttprequest(obsluha, method, url, content, headers) {
    var xmlhttp = (window.XMLHttpRequest ? new XMLHttpRequest : (window.ActiveXObject ? new ActiveXObject("Microsoft.XMLHTTP") : false));
    if (!xmlhttp) {
        return false;
    }
    xmlhttp.open(method, url);
    xmlhttp.onreadystatechange = function() {
        obsluha(xmlhttp);
    };
    if (headers) {
        for (var key in headers) {
            xmlhttp.setRequestHeader(key, headers[key]);
        }
    }
    xmlhttp.send(content);
    return true;
}

//-----------------------------------------------------------------------------
// kontrola formulare (inputy oznacene rel="required")

var styleNormal='btn';
var styleDisabled='btn-dis';

function validateReservation(form){
  
  if(form.res_count.value == '' || 
     (form.email.value != '' && wrong_mail_address(form.email.value)) ||
     form.name.value == '') dis = true;
  else dis = false;  
  
  form.reservation_submit.disabled=dis;
  if(dis) 
    form.reservation_submit.className=styleDisabled;
  else
    form.reservation_submit.className=styleNormal;
}

function clearField(obj, str){
  if(obj.value == str) obj.value='';
}


function insertSmile(code){
  clearField(getObj('textarea'), 'text příspěvku');
  getObj('textarea').value += " " + code + " ";
}

//------------------------------------------------------------------------------
// zobrazeni hlasky o vyprodanem predstaveni a skryti formu

function updateForm(){
  var programID = getObj('programID').value;
  var form = getObj('form');
  var sellout = getObj('sellout');
  
  if(programID != '0'){
    form.style.display = 'block';
    sellout.style.display = 'none';
  }
  else{
    form.style.display = 'none';
    sellout.style.display = 'block';
  }
}