购物车 购买数量的加减

<div class="ofh pb10"> <span class="lab">购买数量</span>

<div class="attr">

<p class="num fl pr" id="goodsNum"><b class="jian" onclick="chgNum(-{$goods_info.qidingnum});">-</b>

<input type="text" name="number" id="number" class="txt fl" value="{$goods_info.qidingnum}"/>

<b class="jia" onclick="chgNum({$goods_info.qidingnum});">+</b></p>

<span class="fl lh30 ml_20"><i class="c_org" id="inventory">--</i></span> </div>

</div>

<script>

function chgNum(a) {

var number = document.getElementById("number");

var p = parseInt(number.value);

if (a >= 1) {

if (p < 1038) number.value = a+p;

}

else {

if (p > 1) number.value = p+a;

}

}

</script>