function center_popup(url,name,w,h,scroll){
LeftPosition = (screen.width) ? (screen.width-w)/2 : 0;
TopPosition = (screen.height) ? (screen.height-h)/2 : 0;
settings = 'height='+h+',width='+w+',top='+TopPosition+',left='+LeftPosition+',scrollbars='+scroll+',resizable='
win = window.open(url,name,settings)
if(win.window.focus){win.window.focus();}
}

  function chkFormularde() {
  
  if (document.formular.email.value == "") {
    alert("Bitte deine E-Mail-Adresse eingeben!");
    document.formular.email.focus();
    return false;
  }
   else if (document.formular.email.value == "deine@email.de") {
    alert("Bitte eine gültige E-Mail-Adresse eingeben!");
    document.formular.email.focus();
    return false;
  }
  else if (document.formular.email.value.indexOf("@") == -1) {
    alert("Deine E-Mail-Adresse ist ungültig!");
    document.formular.email.focus();
    return false;
  }

}

  function chkFormular() {
  if (document.formular.email.value == "") {
    alert("Input-Field 'E-Mail' has not filled out!");
    document.formular.email.focus();
    return false;
  }
  
   if (document.formular.email.value == "your@email.de") {
    alert("Input-Field 'E-Mail' has not filled out correctly!");
    document.formular.email.focus();
    return false;
  }
  
  if (document.formular.email.value.indexOf("@") == -1) {
    alert("Input-Field 'E-Mail' has not filled out correctly");
    document.formular.email.focus();
    return false;
  }
}