js 购物车的数量加减，对应的总价也随机变化

html相关的源码

<div class="goods_num clearfix">
 <div class="num_name fl">数 量：</div>
    <div class="num_add fl">
        <input type="text" name="num" class="num_show fl" value="1">
        <a href="javascript:;" class="add fr">+</a>
        <a href="javascript:;" class="minus fr">-</a>
    </div>
</div>
<div class="total">总价：<em id="price">{{ good.price }}</em>元</div>

js相关

<script>
    $(function () {
        //加号
        var price1 = parseFloat($('#price').text());
        var num = parseInt($('input[name="num"]').attr('value'));
        $('.add').click(function(){
            num++;
            $('input[name="num"]').attr('value',num);
            var total = num * price1;
            $('#price').html(total.toFixed(2));
        });
        //减号
        $('.minus').click(function () {
            if(num>1){
                num--;
                $('input[name="num"]').attr('value',num);
                console.log(num)
                var total = num * price1;
                $('#price').text(total.toFixed(2));
            }
        });
    });
</script>