下面的代码段将显示加号（&；减数量按钮@WooCommerce单一产品页面。Reference

/**
 * @snippet       Plus Minus Quantity Buttons @ WooCommerce Single Product Page
 * @how-to        Watch tutorial @ https://businessbloomer.com/?p=19055
 * @sourcecode    https://businessbloomer.com/?p=90052
 * @author        Rodolfo Melogli
 * @compatible    WooCommerce 3.5.1
 * @donate $9     https://businessbloomer.com/bloomer-armada/
 */

// -------------
// 1. Show Buttons

add_action( \'woocommerce_before_add_to_cart_quantity\', \'bbloomer_display_quantity_plus\' );

function bbloomer_display_quantity_plus() {
   echo \'<button type="button" class="plus" >+</button>\';
}

add_action( \'woocommerce_after_add_to_cart_quantity\', \'bbloomer_display_quantity_minus\' );

function bbloomer_display_quantity_minus() {
   echo \'<button type="button" class="minus" >-</button>\';
}

// -------------
// 2. Trigger jQuery script

add_action( \'wp_footer\', \'bbloomer_add_cart_quantity_plus_minus\' );

function bbloomer_add_cart_quantity_plus_minus() {
   // Only run this on the single product page
   if ( ! is_product() ) return;
   ?>
      <script type="text/javascript">

      jQuery(document).ready(function($){   

         $(\'form.cart\').on( \'click\', \'button.plus, button.minus\', function() {

            // Get current quantity values
            var qty = $( this ).closest( \'form.cart\' ).find( \'.qty\' );
            var val   = parseFloat(qty.val());
            var max = parseFloat(qty.attr( \'max\' ));
            var min = parseFloat(qty.attr( \'min\' ));
            var step = parseFloat(qty.attr( \'step\' ));

            // Change the value if plus or minus
            if ( $( this ).is( \'.plus\' ) ) {
               if ( max && ( max <= val ) ) {
                  qty.val( max );
               } else {
                  qty.val( val + step );
               }
            } else {
               if ( min && ( min >= val ) ) {
                  qty.val( min );
               } else if ( val > 1 ) {
                  qty.val( val - step );
               }
            }

         });

      });

      </script>
   <?php
}