Форум

<a href="?action=DELETE_FROM_COMPARE_LIST&id=<?=$arItem['ID']?>">Удалить</a>

<a href="?action=ADD_TO_COMPARE_LIST&id=<?=$arItem['ID']?>">Добавить в сравнение</a>

<?
$APPLICATION->IncludeComponent(
   "bitrix:catalog.compare.list",
   "",
   array(
      "IBLOCK_TYPE" => $arParams["IBLOCK_TYPE"],
      "IBLOCK_ID" => $arParams["IBLOCK_ID"],
      "NAME" => $arParams["COMPARE_NAME"],
      "DETAIL_URL" => $arResult["FOLDER"].$arResult["URL_TEMPLATES"]["element"],
      "COMPARE_URL" => $arResult["FOLDER"].$arResult["URL_TEMPLATES"]["compare"],
      "ACTION_VARIABLE" => (!empty($arParams["ACTION_VARIABLE"]) ? $arParams["ACTION_VARIABLE"] : "action"),
      "PRODUCT_ID_VARIABLE" => $arParams["PRODUCT_ID_VARIABLE"],
      'POSITION_FIXED' => isset($arParams['COMPARE_POSITION_FIXED']) ? $arParams['COMPARE_POSITION_FIXED'] : '',
      'POSITION' => isset($arParams['COMPARE_POSITION']) ? $arParams['COMPARE_POSITION'] : '',
   ),
   false
);
?>

<input 
      type="checkbox" 
      value="<?=$item['ID'];?>" 
      class="compare-control" 
      <? if (isset($_SESSION[$arParams['COMPARE_NAME']][$item['IBLOCK_ID']]['ITEMS'][$item['ID']])):?>
         checked="checked"
      <? endif;?>
>

$(function(){
   $(document).on('change', '.compare-control', function(){
      var id = $(this).val();
      var url = '/catalog/?action=DELETE_FROM_COMPARE_LIST&ajax_action=Y&id='+id;

      if ($(this).prop('checked')) {
         url = '/catalog/?action=ADD_TO_COMPARE_LIST&ajax_action=Y&id='+id;
      }

      $.get(url, function() {
         BX.onCustomEvent('OnCompareChange');
      });
   })

   BX.addCustomEvent('onCatalogDeleteCompare', function(id) {
      $('.compare-control[value="'+id+'"]').prop('checked', false);
   });
})

$APPLICATION->IncludeComponent(
   'bitrix:catalog.item',
   'catalog',
   array(
      'RESULT' => array(
         'ITEM' => $item,
         'AREA_ID' => $this->GetEditAreaId($uniqueId),
      ),
      'PARAMS' => array(
         'COMPARE_NAME' => $arParams['COMPARE_NAME'],
      )
   ),
   $component,
   array('HIDE_ICONS' => 'Y')
);