function checkForm(){
    document.getElementById("form").action = '/index.html'
    document.getElementById("form").submit();
}

function clearField(x){
  if (document.getElementById(x).value == x){
    document.getElementById(x).value = '';
  }
}

function fillField(x){
  if (document.getElementById(x).value == ''){
    document.getElementById(x).value = x;
  }
}
function screenPopup (URL) {
  MeinFenster = window.open(URL);
  MeinFenster.focus();
}