/**
 * Check All Checkboxes
 * @author Jens Hatlak <jh@junetz.de>
 * @version 2010-07-15
 */
let fields = window.content.document.getElementsByTagName('input');
for (let i = 0; i < fields.length; ++i)
  if (fields[i].type == 'checkbox' && fields[i].disabled == false)
    fields[i].checked = true;