// set default to false
document.MM_returnvalue = false;

// actual check
function CheckForm() {
	var errors = '';
  for (i=0; i<(CheckForm.arguments.length); i++) {
    objStr = CheckForm.arguments[i];
	field = eval(objStr);
    field.name = (field.name)?field.name:objStr;
		if (field.value != '') {
		if (field.name == 'email') {
				if ( !field.value.match(/^\w+([\.-]?\w+)*@\w+([\.-]?\w+)*(\.\w{2,4})+$/) ) {
					errors += '- Eine gültige E-Mail-Adresse.\n';
				}
      }
		}
	else if (field.name == 'name') errors += '- Ihren Namen.\n';
	else if (field.name == 'telefon') errors += '- Ihre Telefonnummer.\n';
	else if (field.name == 'email') errors += '- Ihre E-Mail-Adresse.\n';
	else if (field.name == 'message') errors += '- Ihre Bemerkung.\n';
	}
	if ( errors ) {
		var errorstr = 'Füllen Sie bitte nachstehende Felder vollständig aus:\n\n'+errors;
		alert(errorstr);
		document.MM_returnvalue = false;
	}
	else {
		document.MM_returnvalue = true;
	}
}