js返回顶部

大家好，又见面了，我是你们的朋友全栈君。
回到顶部
<head>
	<meta charset="UTF-8">
	<meta name="viewport" content="width=device-width, initial-scale=1.0">
	<meta http-equiv="X-UA-Compatible" content="ie=edge">
	<title>Document</title>
	<script src="http://lib.sinaapp.com/js/jquery/2.0.2/jquery-2.0.2.min.js"></script>
	<style>
		#gotoTop {
      	box-sizing: border-box;
      	display: none;
      	position: fixed;
      	bottom: 10%;
      	right: 20px;
      	cursor: pointer;
      	padding: 9px 2px;
      	width: 40px;
      	height: 40px; text-align : center;
      	border: 1px solid #e0e0e0;
      	z-index: 99;
      	background: #000
      		url("data:image/png;base64,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");
      	background-size: 100% auto;
      	text-align: center;
      }
       
      #gotoTop {
      	_position: absolute;
      	_top: expression(documentElement.scrollTop + documentElement.clientHeight * 3/
      		4 + "px")
      }
       
      #gotoTop.hover {
      	background: #165ec5
      		url("data:image/png;base64,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");
      	text-decoration: none;
      	background-size: 100% auto;
      }
       
      .fay-tip:hover p{
      	display:block;
      	transform-origin: 100% 0%;
       
      	-webkit-animation: topFadeIn 0.4s ease-in-out;
      	animation: topFadeIn 0.4s ease-in-out;
      }
       
      .fay-tip p{
      	display:none;
      	background-color: #494949;
      	padding: 10px;
      	width: 80px;
      	position: absolute;
      	box-shadow: 1px 1px 1px rgba(0, 0, 0, 0.2);
      	right: 38px;
      	color: #FFF;
      	font-size: 13px;
      	line-height: 1.4;
      	top:0;
      	margin: 0 0 10px;
      }
       
      .fay-tip p:before{
      	position: absolute;
      	content: '';
      	width:0;
      	height: 0;
      	border:6px solid transparent;
      	border-bottom-color:#494949;
      	right:-12px;
      	top:10px;
      	border-color: transparent transparent transparent #494949;
      }
       
      .fay-tip p:after{
      	width:100%;
      	height:40px;
      	content:'';
      	position: absolute;
      	top:0;
      	left:80px;
      }
       
      @-webkit-keyframes topFadeIn {
      	0% { 
      		right:80px;
      		opacity:0; 
      		transform: scale(0.6);
      	}
       
      	100% {
      		right:38px;
      		opacity:100%;
      		transform: scale(1);
      	}
      }
       
      @keyframes topFadeIn {
      	0% {
      		right:80px;
      		opacity:0; 
      	}
      	100% {
      		right:38px;
      		opacity:100%; 
      	}
      }
    </style>
</head>

<body id="page">
	<h1>返回顶部</h1>
	<h2>返回顶部</h2>
	<h3>返回顶部</h3>
	<h4>返回顶部</h4>
	<h5>返回顶部</h5>
	<h1>返回顶部</h1>
	<h2>返回顶部</h2>
	<h3>返回顶部</h3>
	<h4>返回顶部</h4>
	<h5>返回顶部</h5>
	<h1>返回顶部</h1>
	<h2>返回顶部</h2>
	<h3>返回顶部</h3>
	<h4>返回顶部</h4>
	<h5>返回顶部</h5>
	<h1>返回顶部</h1>
	<h2>返回顶部</h2>
	<h3>返回顶部</h3>
	<h4>返回顶部</h4>
	<h5>返回顶部</h5>
	<h1>返回顶部</h1>
	<h2>返回顶部</h2>
	<h3>返回顶部</h3>
	<h4>返回顶部</h4>
	<h5>返回顶部</h5>
	<script type="text/javascript" src="jquery.min.js"></script>
	<script type="text/javascript" src="script.js"></script>
</body>
<script type="text/javascript">
	gotoTop();
	function gotoTop(min_height) {
		// 预定义返回顶部的html代码，它的css样式默认为不显示
		var gotoTop_html = '<div id="gotoTop" class="fay-tip"><p>返回顶部</p></div>';
		// 将返回顶部的html代码插入页面上id为page的元素的末尾
		$("#page").append(gotoTop_html);
		$("#gotoTop").click( // 定义返回顶部点击向上滚动的动画
			function() {
				$('html,body').animate({
					scrollTop: 0
				}, 700);
			}).hover( // 为返回顶部增加鼠标进入的反馈效果，用添加删除css类实现
			function() {
				$(this).addClass("hover");
			},
			function() {
				$(this).removeClass("hover");
			});
		// 获取页面的最小高度，无传入值则默认为600像素
		min_height ? min_height = min_height : min_height = 0;
		// 为窗口的scroll事件绑定处理函数
		$(window).scroll(function() {
			// 获取窗口的滚动条的垂直位置
			var s = $(window).scrollTop();
			// 当窗口的滚动条的垂直位置大于页面的最小高度时，让返回顶部元素渐现，否则渐隐
			if (s > min_height) {
				$("#gotoTop").fadeIn(100);
			} else {
				$("#gotoTop").fadeOut(200);
			}
		});
	}
</script>
发布者：全栈程序员-站长，转载请注明出处：https://javaforall.net/158692.html原文链接：https://javaforall.net