function checkUser() 
{
    var savedData = decodeURIComponent(document.cookie);
    var storedLogin, storedPassword,storedNom,storedPrenom;
    var login = document.getElementById("login").value;
    var passwd = document.getElementById("passwd").value;
    var dataArray = savedData.split("; ");
    for (var i = 0; i < dataArray.length; ++i)
        {
        if (dataArray[i].substring(0, dataArray[i].indexOf("=")) == "login")  
           {
           storedLogin = dataArray[i].substring(dataArray[i].indexOf("=") + 1, dataArray[i].length);
           }
        if (dataArray[i].substring(0, dataArray[i].indexOf("=")) == "passwd") 
           {
           storedPassword = dataArray[i].substring(dataArray[i].indexOf("=") + 1, dataArray[i].length);
           }
       if (dataArray[i].substring(0, dataArray[i].indexOf("=")) == "nom") 
          {
           storedNom = dataArray[i].substring(dataArray[i].indexOf("=") + 1, dataArray[i].length);
          }
       if (dataArray[i].substring(0, dataArray[i].indexOf("=")) == "prenom")
          {
           storedPrenom = dataArray[i].substring(dataArray[i].indexOf("=") + 1, dataArray[i].length);
          }
        }
    if (login != "" && passwd != "")
       {
       if (login == storedLogin && passwd == storedPassword) 
          {
          document.cookie = "login=" + encodeURIComponent("successful");
          alert("Vous étes connecté");
          document.getElementById("divConnected").innerHTML ='<p style="background-color:Orange; color:White">' + storedNom + ',' + storedPrenom +'</p>'
          return true;
          }
  }
  alert("Login ou mot de passe incorrect");
  return false;
}