function customShopCheckForm( form ){
  try {
    var inputs = Form.getElements( form ),
        filled = true;

    for ( i = 0; i < inputs.length; i++ ){
      var input = inputs[i];
      if ( input.getAttribute( 'must' ) ) {
        if ( ! input.getValue() ){
          if ( input.type == 'checkbox' ){
            input.up(1).setStyle( { color: 'red' } );
            filled = false;
          } else {
            input.setStyle( { borderColor: 'red' } );
            filled = false;
          }
        } else {
          input.up(1).setStyle( { color: '' } );
          input.setStyle( { borderColor: '' } );
        }
      }
    }
    return filled;
  } catch ( e ){
    Log.write( e );
    return false;
  }
}