<!--{if $usecategory == 1}-->
あああ
<!--{elseif $usecategory == 2}-->
いいい
<!--{/if}-->

<div class="category<!--{$usecategory}-->">
<input type="text" id="category<!--{$usecategory}-->" name="category<!--{$usecategory}-->" />
</div>

<!--{if $objCartSess[$productTypeId][$i]["productsClass"]["product_id"] == 1}-->
<!--カート内商品の親カテゴリがIDが1なら-->
<div class="category1">
<input type="text" id="category1" name="category1"  />
</div>
<!--{elseif $objCartSess[$productTypeId][$i]["productsClass"]["product_id"] == 2}}-->
<!--カート内商品の親カテゴリがIDが2なら-->
<div class="category2">
<input type="text" id="category2" name="category2"  />
</div>
<!--{/if }-->

  function isTargetProduct($productTypeId) {
       $max = $this->getMax($productTypeId);
       
        $objQuery =& SC_Query_Ex::getSingletonInstance();
        $HelperCategory = new SC_Helper_Category;
        $query = '
        SELECT
            category_id 
        FROM 
            dtb_product_categories
        WHERE
            product_id = ?
        LIMIT 1
       
       ';

       for($i = 0; $i <= $max; $i++) {
           if($this->cartSession[$productTypeId][$i]['cart_no'] != "") {
               $category_ary = $HelperCategory->getTreeTrail(SC_Query_Ex::getSingletonInstance()->getOne($query,array($this->cartSession[$productTypeId][$i]["productsClass"]["product_id"])),true);
               return $category_ary[0];
           }
       }
   }

    function action(){
        parent::action();

        $objCartSess = new SC_CartSession_Ex();
        $this->usecategory = $objCartSess->isTargetProduct($this->cartKey);
    }

<div class="category<!--{$usecategory}-->">
<input type="text" id="category<!--{$usecategory}-->" name="category<!--{$usecategory}-->" />
</div>

<!--親カテゴリが1番なら-->
<div class="category1">
<input type="text" id="category1" name="category1"  />
</div>

<!--親カテゴリが2番なら-->
<div class="category2">
<input type="text" id="category2" name="category2" />
</div>

   function isTargetProduct($productTypeId,$productId) {
       $max = $this->getMax($productTypeId);
       for($i = 0; $i <= $max; $i++) {
           if($this->cartSession[$productTypeId][$i]['cart_no'] != "") {
               if( $this->cartSession[$productTypeId][$i]["productsClass"]["product_id"]==$productId){
                   return true;
               }
 
           }
       }
       return false;
   }

$this->isHoge = $objCartSess->isTargetProduct($cart_key,$target_productId);