siblings,parent,children定位元素

$(".mid-sl .sl-left").click(function(event) {
        var vl = $(this).siblings("input").val();
        var dj = $(this).parent().siblings(".mid-dj").children('span').text();
        if (vl>1) {
            vl--;
            $(this).siblings("input").val(vl);
            $(this).parent().siblings(".mid-je").children('span').text(dj*vl);
        }
    });

<div class="mid-sl f-l">
                    <a href="JavaScript:;" class="sl-left" id="${cartI.productExt.pid}" name="reduce">-</a>
                    <input type="text" name="num" id="${cartI.productExt.pid}" value="${cartI.count}" />
                    <a href="JavaScript:;" class="sl-right" id="${cartI.productExt.pid}" name="plus">+</a>
                </div>
                <p class="mid-dj f-l">¥ <span>${cartI.price}</span></p>
                <p class="mid-je f-l">¥ <span>${cartI.sum}</span></p>