How do you toggle checkall?

How do you toggle checkall?

I'm using jqtransform and here's the function for the checkboxes. What code would I use the select/deselect all?

$.fn.jqTransCheckBox = function(){
   return this.each(function(){
      if($(this).hasClass('jqTransformHidden')) {return;}

      var $input = $(this);
      var inputSelf = this;

      //set the click on the label
      var oLabel=jqTransformGetLabel($input);
      oLabel && oLabel.click(function(){aLink.trigger('click');});

      var aLink = $('<a href="#" class="jqTransformCheckbox"></a>');
      //wrap and add the link
      $input.addClass('jqTransformHidden').wrap('<span class="jqTransformCheckboxWrapper"></span>').parent().prepend(aLink);
      //on change, change the class of the link
      $input.change(function(){
         this.checked && aLink.addClass('jqTransformChecked') || aLink.removeClass('jqTransformChecked');
         return true;
      });
      // Click Handler, trigger the click and change event on the input
      aLink.click(function(){
         //do nothing if the original input is disabled
         if($input.attr('disabled')){return false;}
         //trigger the envents on the input object
         $input.trigger('click').trigger("change");
         return false;
      });

      // set the default state
      this.checked && aLink.addClass('jqTransformChecked');
   });
};