Only load media model when needed in watermark settings (ILovePDF plugin)

watermark-settings.php

<?php

// @see https://plugins.trac.wordpress.org/browser/ilovepdf/trunk/admin/watermark-settings.php#L423,
// @see https://wordpress.org/support/topic/javascript-error-and-solution/

function ilove_pdf_media_selector_print_scripts() {
  $page = isset( $_GET['page'] ) ? $_GET['page'] : '';
  $tab = isset( $_GET['tab'] ) ? $_GET['tab'] : '';

  if ( $page == 'ilove-pdf-content-setting' && $tab == 'watermark_options' ) {
    $options = get_option('ilove_pdf_display_settings_format_watermark');

    if ( isset( $options['ilove_pdf_format_watermark_mode'] ) ) {
      $my_saved_attachment_post_id = isset($options['ilove_pdf_format_watermark_image']) && $options['ilove_pdf_format_watermark_image'] != '' ? $options['ilove_pdf_format_watermark_image'] : 0;
      ?>
      <script type='text/javascript'>
          jQuery( document ).ready( function( $ ) {
              // Uploading files
              var file_frame;
              var wp_media_post_id = wp.media.model.settings.post.id; // Store the old id
              var set_to_post_id = <?php echo $my_saved_attachment_post_id; ?>; // Set this
              jQuery('#upload_image_button').on('click', function( event ){
                  event.preventDefault();
                  // If the media frame already exists, reopen it.
                  if ( file_frame ) {
                      // Set the post ID to what we want
                      file_frame.uploader.uploader.param( 'post_id', set_to_post_id );
                      // Open frame
                      file_frame.open();
                      return;
                  } else {
                      // Set the wp.media post id so the uploader grabs the ID we want when initialised
                      wp.media.model.settings.post.id = set_to_post_id;
                  }
                  // Create the media frame.
                  file_frame = wp.media.frames.file_frame = wp.media({
                      title: '<?php echo __('Select a image to upload','ilovepdf')?>',
                      button: {
                          text: '<?php echo __('Use this image','ilovepdf')?>',
                      },
                      multiple: false // Set to true to allow multiple files to be selected
                  });
                  // When an image is selected, run a callback.
                  file_frame.on( 'select', function() {
                      // We set multiple to false so only get one image from the uploader
                      attachment = file_frame.state().get('selection').first().toJSON();
                      // Do something with attachment.id and/or attachment.url here
                      $( '#image-preview' ).attr( 'src', attachment.url ).css( 'width', 'auto' );
                      $( '#image_attachment_id' ).val( attachment.url );
                      $( '#ilove_pdf_format_watermark_image' ).val( attachment.id );
                      // Restore the main post ID
                      wp.media.model.settings.post.id = wp_media_post_id;
                  });
                      // Finally, open the modal
                      file_frame.open();
              });
              // Restore the main ID when the add media button is pressed
              jQuery( 'a.add_media' ).on( 'click', function() {
                  wp.media.model.settings.post.id = wp_media_post_id;
              });
          });
      </script>
      <?php
    }
  }
}
add_action( 'admin_footer', 'ilove_pdf_media_selector_print_scripts' );