update product quantity on check out page magento

update product quantity on check out page magento

you can do it by editing item.phtml (template/checkout/onepage/review/item.phtml) and these lines after line no #47

    <td class="a-center"><?php echo $_item->getQty() ?></td>   
        <td class="a-center">
            <input name="cart[<?php echo $_item->getId() ?>][qty]" value="<?php echo $this->getQty() ?>" size="4" name="update_cart_action" id="cup_<?php echo $_item->getId() ?>"  class="input-text qty" maxlength="12" />
        </td>
       <td> <button type="submit" name="update_cart_action" value="update_qty" title="<?php echo $this->__('shopping-cart-table'); ?>" id="up_<?php echo $_item->getId() ?>" class="button btn-update"><span><span><?php echo $this->__('Update'); ?></span></span></button><td>

and put Jquery code at the end

    <script type="text/javascript">
    jQuery(document).ready(function(){
        jQuery(".btn-update").click(function(){

            var id = "#c"+this.id;
            var quan = jQuery(id).val();
            var lastChar = id.substr(id.length - 1);

            jQuery.ajax({
                url: "<?php echo Mage::getBaseUrl(); ?>checkout/cart/updatePosts/",
                data: "cart["+lastChar+"][qty]="+quan,
                async: false,
                    success: function(html){

                        location.reload();

                    }
            })
        })
    })
    </script>

now override cartcontroller.php and place all the functions of the original cartcontroller.php and rename function updatePostAction by function updatePostsAction.
and change the redirect path to $this->_redirect(‘checkout/onepage’);