numbox在某些情况下每次点击会+2 而不是+1

<div class="mui-numbox" data-numbox-min='1'>
<button class="mui-btn mui-btn-numbox-minus" type="button">-</button>
<input class="mui-input-numbox goodsCount" type="number" value="0" />
<button class="mui-btn mui-btn-numbox-plus" type="button">+</button>
</div>

某些时候每点击一次加2而不是加1