function getOpacity(e) {if (!e.filters) {if (e.style.opacity) {return parseFloat(e.style.opacity) * 100;}}try {return e.filters.item(‘alpha‘).opacity;} catch (o) {return 100;}}
获得指定元素的透明度值
原文：http://www.cnblogs.com/freeze89/p/4152405.html
