source: sipes/cord/misc/teaser.js @ b9d4e2e

/**
 * Auto-attach for teaser behavior.
 *
 * Note: depends on resizable textareas.
 */
Drupal.behaviors.teaser = function(context) {
  // This breaks in Konqueror. Prevent it from running.
  if (/KDE/.test(navigator.vendor)) {
    return;
  }

  $('textarea.teaser:not(.teaser-processed)', context).each(function() {
    var teaser = $(this).addClass('teaser-processed');

    // Move teaser textarea before body, and remove its form-item wrapper.
    var body = $('#'+ Drupal.settings.teaser[this.id]);
    var checkbox = $('#'+ Drupal.settings.teaserCheckbox[this.id]).parent();
    var checked = $(checkbox).children('input').attr('checked') ? true : false;
    var parent = teaser[0].parentNode;
    $(body).before(teaser);
    $(parent).remove();

    function trim(text) {
      return text.replace(/^\s+/g, '').replace(/\s+$/g, '');
    }

    // Join the teaser back to the body.
    function join_teaser() {
      if (teaser.val()) {
        body.val(trim(teaser.val()) +'\r\n\r\n'+ trim(body.val()));
      }
      // Empty, hide and disable teaser.
      teaser[0].value = '';
      $(teaser).attr('disabled', 'disabled');
      $(teaser).parent().slideUp('fast');
      // Change label.
      $(this).val(Drupal.t('Split summary at cursor'));
      // Hide separate teaser checkbox.
      $(checkbox).hide();
      // Force a hidden checkbox to be checked (to ensure that the body is
      // correctly processed on form submit when teaser/body are in joined
      // state), and remember the current checked status.
      checked = $(checkbox).children('input').attr('checked') ? true : false;
      $(checkbox).children('input').attr('checked', true);
    }

    // Split the teaser from the body.
    function split_teaser() {
      body[0].focus();
      var selection = Drupal.getSelection(body[0]);
      var split = selection.start;
      var text = body.val();

      // Note: using val() fails sometimes. jQuery bug?
      teaser[0].value = trim(text.slice(0, split));
      body[0].value = trim(text.slice(split));
      // Reveal and enable teaser
      $(teaser).attr('disabled', '');
      $(teaser).parent().slideDown('fast');
      // Change label
      $(this).val(Drupal.t('Join summary'));
      // Show separate teaser checkbox, restore checked value.
      $(checkbox).show().children('input').attr('checked', checked);
    }

    // Add split/join button.
    var button = $('<div class="teaser-button-wrapper"><input type="button" class="teaser-button" /></div>');
    var include = $('#'+ this.id.substring(0, this.id.length - 2) +'include');
    $(include).parent().parent().before(button);

    // Extract the teaser from the body, if set. Otherwise, stay in joined mode.
    var text = body.val().split('<!--break-->');
    if (text.length >= 2) {
      teaser[0].value = trim(text.shift());
      body[0].value = trim(text.join('<!--break-->'));
      $(teaser).attr('disabled', '');
      $('input', button).val(Drupal.t('Join summary')).toggle(join_teaser, split_teaser);
    }
    else {
      $('input', button).val(Drupal.t('Split summary at cursor')).toggle(split_teaser, join_teaser);
      $(checkbox).hide().children('input').attr('checked', true);
    }

    // Make sure that textarea.js has done its magic to ensure proper visibility state.
    if (Drupal.behaviors.textarea && teaser.is(('.form-textarea:not(.textarea-processed)'))) {
      Drupal.behaviors.textarea(teaser.parentNode);
    }
    // Set initial visibility
    if ($(teaser).is(':disabled')) {
      $(teaser).parent().hide();
    }

  });
};