有滚动条得情况下，求标签离浏览器视口高度

 

使用：getElementViewTop($(".product .tab a")[0])  //注意一定要加[0]

//有滚动条得情况下，求标签离浏览器视口高度

function getElementViewTop(element) {
var actualTop = element.offsetTop;
var current = element.offsetParent;
var elementScrollTop;
while (current !== null) {
actualTop += current.offsetTop;
current = current.offsetParent;
}
elementScrollTop = document.documentElement.scrollTop || window.pageYOffset || document.body.scrollTop;
return actualTop - elementScrollTop;
}