var btn_recherche = document.getElementById("btn_recherche")
var lst_vdepart = document.getElementById("lst_vdepart")
var depart_vide = document.getElementById("depart_vide")
var txt_destination = document.getElementById("txt_destination")
var destination_vide = document.getElementById("destination_vide")
var txt_date = document.getElementById("txt_date")
var date_vide = document.getElementById("date_vide")
var form_destination = document.getElementById("form_destination")
var btn_french = document.getElementById("btn_french")
var btn_english = document.getElementById("btn_english")
var btn_german = document.getElementById("btn_german")

depart_vide.style.display = "none"
destination_vide.style.display = "none"
date_vide.style.display = "none"

if (window.location.search != "")
{
  longueur = window.location.search.length - 1;
  data = window.location.search.substr(1,longueur);
  donnees = data.split("&");
  urlvar = new Array();
  urlvarnum = new Array();
  for (var i=0; i < donnees.length; i++)
  {
    position = donnees[i].indexOf("=");
    variable = donnees[i].substr(0,position);
    pos = position + 1;
    valeur = decodeURI(donnees[i].substr(pos,donnees[i].length));
    while (valeur.search(/\+/) != -1)
      valeur = valeur.replace(/\+/," ");
    while (valeur.search(/%2F/) != -1)
      valeur = valeur.replace(/%2F/,"/");
    urlvar[variable] = valeur;
    urlvarnum[i] = valeur;
  }
} //si l'adresse de départ est "http://www.mapage.com/index.htm?nom=dupond&prenom=jean&age=50+ans", alors urlvar['nom'] vaut 'dupond', urlvar['prenom'] vaut 'jean', et urlvar['age'] vaut '50 ans'

function remplir_champs()
{
  if(typeof urlvar['id_vdepart'] != "undefined")
    for (i=0; i< lst_vdepart.options.length; i++)
    {
      if(lst_vdepart.options[i].value == urlvar['id_vdepart'])
        lst_vdepart.options.selectedIndex = i;
    }
  else
    lst_vdepart.options.selectedIndex = 0;

  if(typeof urlvar['txt_destination'] != "undefined")
    txt_destination.value = urlvar['txt_destination']
  else
    txt_destination.value = ""
    
  if(typeof urlvar['txt_date'] != "undefined")
    txt_date.value = urlvar['txt_date']
  else
    txt_date.value = ""
}

function verifier_form()
{
  raz()
  
  if(lst_vdepart.value == "0")
  {
    depart_vide.style.display = "block"
  }
  if(txt_destination.value == "")
  {
    destination_vide.style.display = "block"
  }
  if(txt_date.value == "")
  {
    date_vide.style.display = "block"
  }
  
  if(depart_vide.style.display == "none" && destination_vide.style.display == "none" && date_vide.style.display == "none")
    form_destination.submit()
}

function raz()
{
  depart_vide.style.display = "none"
  destination_vide.style.display = "none"
  date_vide.style.display = "none"
}

function changer_langue(langue)
{
  var chaine_adresse = document.location.href
  if(chaine_adresse.indexOf("language=") != -1)
    chaine_adresse = chaine_adresse.replace(chaine_adresse.substr(chaine_adresse.indexOf("language="),11),"language="+langue)
  else
    chaine_adresse = chaine_adresse + "?language=" + langue
  window.location.href = chaine_adresse
}

btn_french.onclick = function(){changer_langue("FR")};
btn_english.onclick = function(){changer_langue("EN")};
btn_german.onclick = function(){changer_langue("GR")};

window.onload = remplir_champs
btn_recherche.onclick = verifier_form