js input输入数量控制

<div class="w-number" >

<a class="w-number-btn w-number-btn-minus" pro="minus" href="javascript:void(0);">－</a>

<input class="w-number-input" pro="input" type="text" value="5">

<a class="w-number-btn w-number-btn-plus" pro="plus" href="javascript:void(0);">＋</a>

</div>

window.ONE_GOODS = {
status : 1,
period : 304080621,
goods : {
gid : 1851,
gname : '平安金',
price : 3688,
buyable : true,
buyUnit : 10
},
existingTimes : 3485
};

//数量输入框 window.ONE_GOODS
var $numInput = $(".w-number-input");
var oBuyNum = parseInt($numInput.val());
//-
$(".w-number-btn.w-number-btn-minus").click(function(){
var buyNum = $numInput.val() - $numInput.val() % ONE_GOODS.goods.buyUnit - ONE_GOODS.goods.buyUnit;
oBuyNum = buyNum >= ONE_GOODS.goods.buyUnit ? buyNum : ONE_GOODS.goods.buyUnit;
$numInput.val(oBuyNum);
});
//+
$(".w-number-btn.w-number-btn-plus").click(function(){
var buyNum = parseInt($numInput.val()) - $numInput.val() % ONE_GOODS.goods.buyUnit + ONE_GOODS.goods.buyUnit;
oBuyNum = buyNum <= ONE_GOODS.existingTimes ? buyNum : ONE_GOODS.existingTimes;
$numInput.val(oBuyNum);
});
//输入
$numInput.hover(function(){selectText($numInput[0],0,$numInput.val().length);},function(){});
$(".w-number-input").change(function(){
var buyNum = $numInput.val();
if(/^d+$/.test(buyNum)){
if(buyNum < ONE_GOODS.goods.buyUnit){
oBuyNum = ONE_GOODS.goods.buyUnit;
}else if( buyNum > ONE_GOODS.existingTimes){
oBuyNum = ONE_GOODS.existingTimes;
}else if(buyNum%ONE_GOODS.goods.buyUnit > 0){
oBuyNum = buyNum > ONE_GOODS.goods.buyUnit ? buyNum - buyNum % ONE_GOODS.goods.buyUnit + ONE_GOODS.goods.buyUnit : ONE_GOODS.goods.buyUnit;
}
}
$numInput.val(oBuyNum);
});