jQuery checkbox utilities: check range, master toggle box, check/uncheck all.

jquery.checkboxes.js

// jQuery checkbox utility plugin.
// Triggers "change" events on the checkboxes.
// By Henrik Nyh <http://henrik.nyh.se> 2009-04-27 under the MIT License.

(function($) {

  function makeChecked($checkboxes, checked) {
    return $checkboxes.prop("checked", checked).trigger("change");
  }

  // Check a range of boxes by clicking one, then another while holding Shift or Command.
  // Code from http://www.barneyb.com/barneyblog/projects/jquery-checkbox-range-selection/
  // modified to support Command and so it can be reapplied after JS re-sort without issues.
  //   $('#container :checkbox').enableCheckboxRangeSelection();
  $.fn.enableCheckboxRangeSelection = function() {
    var lastCheckbox = null;
    var $spec = this;
    $spec.unbind("click.checkboxrange");
    $spec.bind("click.checkboxrange", function(e) {
      if (lastCheckbox != null && (e.shiftKey || e.metaKey)) {
        var $checkboxes = $spec.slice(
          Math.min($spec.index(lastCheckbox), $spec.index(e.target)),
          Math.max($spec.index(lastCheckbox), $spec.index(e.target)) + 1
        )
        makeChecked($checkboxes, e.target.checked);
      }
      lastCheckbox = e.target;
    });
    return $spec;
  };

  // $(':checkbox').checkAll();
  $.fn.checkAll = function() {
    return makeChecked($(this), true);
  };

  // $(':checkbox').uncheckAll();
  $.fn.uncheckAll = function() {
    return makeChecked($(this), false);
  }

  // Master checkbox that can check/uncheck other checkboxes:
  //   $('#slaves :checkbox').checkAllWith('#master:checkbox');
  jQuery.fn.checkAllWith = function(master) {
    $slaves = $(this);
    $master = $(master);

    // If the control box is initially checked, check the others, but not the other way around.
    if ($master.prop('checked')) {
      makeChecked($slaves, true);
    }

    (function($master, $slaves) {  // Closure to allow multiple checkAllWith in one page
      $master.click(function() {
        makeChecked($slaves, !!$master.prop('checked'));
      });
    })($master, $slaves);

    return $slaves;
  };

})(jQuery);

Nice! I have the shift-selection feature done into a jQuery plugin, but I'm using the $.fn.prop instead of $.fn.attr. Take a look at it and if you feel like contributing you are welcome: http://rmariuzzo.github.io/checkboxes.js/

Changed attr -> prop in the Gist for compatibility with jQuery 1.9+.