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function hookProductFormBtn(){ $(".product-form__minus_btn").click(function(){ event.preventDefault(); var current_quantity = parseFloat($(".product-form__quantity").val()); if (current_quantity-1 > 0) { $(".product-form__quantity").val(current_quantity-1); } else { $(".product-form__quantity").val(1); } }); $(".product-form__plus_btn").click(function(){ event.preventDefault(); var current_quantity = parseFloat($(".product-form__quantity").val()); $(".product-form__quantity").val(current_quantity+1); }); }; hookProductFormBtn();