接上一个文章给动画加一个先快后慢的动作!

<!DOCTYPE html>
<html lang="en">

	<head>
		<meta charset="UTF-8">
		<title>Title</title>
		<style>
			* {
				margin: 0;
				padding: 0;
				font-size: 50px;
			}
			
			body {
				/*height:1000px;*/
			}
			
			div {
				width: 500px;
				height: 3000px;
				background: pink;
				margin: 20px auto;
				/*padding: 100px;*/
				border: 50px solid;
				overflow: auto;
			}
			
			h1 {
				height: 1000px;
				background: blue;
			}
			
			button {
				position: fixed;
				right: 40px;
				bottom: 100px;
			}
		</style>
	</head>

	<body>

		<div>
			<h1></h1>
		</div>
		<button>返回顶部</button>

		<script>
			var oDiv = document.querySelector("div");
			var oBtn = document.querySelector("button");
			console.log(window);
			oBtn.onclick = function() {
				//     document.documentElement.scrollTop=100;
				timer = setInterval("runToTop()", 0);
			}

			function runToTop() {
				a1 = document.documentElement.scrollTop
				if (a1 > 1000) {
					a1 = a1 - 10;
					window.scrollTo(0, a1);
				}
				if (a1 < 1000) {
					a1 = a1 - 5;
					window.scrollTo(0, a1);
				}
				if (a1 < 0) {
					window.scrollTo(0, 0);
					clearInterval(timer);
				}
			}

猜你喜欢

转载自blog.csdn.net/weixin_44081699/article/details/86062423
今日推荐