Javascript 检测滚动条何时到达 div 顶部？
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Detect when scrollbar reaches top of div?
提问by Wilfred
I'm trying to animate a boxShadow on the scroll event of my #container div. Everything works except I can't figure out a good way to detect the scrollbar reaching the top so that the boxShadows can animate out. This is my code so far
我正在尝试在 #container div 的滚动事件上为 boxShadow 设置动画。一切正常，除了我找不到检测滚动条到达顶部的好方法，以便 boxShadows 可以设置动画。到目前为止，这是我的代码
$('#container').scroll(
function()
{
$('#white').animate(
{
boxShadow: "0 8px 8px -7px #696868"
},
"fast");
if ($('#container').scrollTop() == 0)
{
$('#white').animate(
{
boxShadow: "0 0 0 0 #696868"
},
"fast");
}
}
);
I've added a demo. The initial on scroll animate works perfectly, but when the bar returns to top their is a rather long delay before the second animation kicks in. http://jsfiddle.net/JYqC3/14/
我添加了一个演示。滚动动画的初始效果完美，但是当栏返回顶部时，在第二个动画开始之前会有相当长的延迟。http://jsfiddle.net/JYqC3/14/
回答by Dhiraj
Hope this helps
希望这可以帮助
Used .scrollTop
$('#my_div').scroll(function() {
var pos = $('#my_div').scrollTop();
if (pos == 0) {
alert('top of the div');
}
});
EDIT:better animation added to demo
编辑：更好的动画添加到演示
