function validEmail (email)
{
  invalidChars = " /:,;"
  if (email=="") { return false }
  for (i=0; i<invalidChars.length; i++)
  {
    badChar = invalidChars.charAt(i)
    if (email.indexOf (badChar, 0) != -1) { return false }
  }
  atPos = email.indexOf ("@", 0)
  if ((atPos == -1) || (atPos == 0)) { return false }
  if (email.indexOf ("@", atPos+1) != -1) { return false }
  periodPos = email.indexOf (".", atPos)
  if ((periodPos == -1) || (periodPos == atPos+1)) { return false }
  if (periodPos+3>email.length == -1) { return false }
  return true
}
function logowanie(form)
{
  if (!(form.login.value))
  {
    alert ("Wpisz login.");
    form.login.focus()
    form.login.select() 
    return false
  }
  if (!(form.pass.value))
  {
    alert ("Wpisz haslo.");
    form.pass.focus()
    form.pass.select() 
    return false
  }
}