(转)JS兑现锚点 _JavaScript

(转)JS实现锚点
test.js

// 说明 ：用 Javascript 实现锚点(Anchor)间平滑跳转

// 来源 ：ThickBox 2.1

// 整理 ：Yanfu Xie [xieyanfu@yahoo.com.cn]

// 网址 ：http://www.codebit.cn

// 日期 ：07.01.17

 

// 转换为数字

function intval(v)

{

v = parseInt(v);

return isNaN(v) ? 0 : v;

}

 

// 获取元素信息

function getPos(e)

{

var l = 0;

var t = 0;

var w = intval(e.style.width);

var h = intval(e.style.height);

var wb = e.offsetWidth;

var hb = e.offsetHeight;

while (e.offsetParent){

l += e.offsetLeft + (e.currentStyle?intval(e.currentStyle.borderLeftWidth):0);

t += e.offsetTop + (e.currentStyle?intval(e.currentStyle.borderTopWidth):0);

e = e.offsetParent;

}

l += e.offsetLeft + (e.currentStyle?intval(e.currentStyle.borderLeftWidth):0);

t += e.offsetTop + (e.currentStyle?intval(e.currentStyle.borderTopWidth):0);

return {x:l, y:t, w:w, h:h, wb:wb, hb:hb};

}

 

// 获取滚动条信息

function getScroll()

{

var t, l, w, h;


if (document.documentElement && document.documentElement.scrollTop) {

t = document.documentElement.scrollTop;

l = document.documentElement.scrollLeft;

w = document.documentElement.scrollWidth;

h = document.documentElement.scrollHeight;

} else if (document.body) {

t = document.body.scrollTop;

l = document.body.scrollLeft;

w = document.body.scrollWidth;

h = document.body.scrollHeight;

}

return { t: t, l: l, w: w, h: h };

}

 

// 锚点(Anchor)间平滑跳转

function scroller(el, duration)

{

if(typeof el != 'object') { el = document.getElementById(el); }

 

if(!el) return;

 

var z = this;

z.el = el;

z.p = getPos(el);

z.s = getScroll();

z.clear = function(){window.clearInterval(z.timer);z.timer=null};

z.t=(new Date).getTime();

 

z.step = function(){

var t = (new Date).getTime();

var p = (t - z.t) / duration;

if (t >= duration + z.t) {

z.clear();

window.setTimeout(function(){z.scroll(z.p.y, z.p.x)},13);

} else {

st = ((-Math.cos(p*Math.PI)/2) + 0.5) * (z.p.y-z.s.t) + z.s.t;

sl = ((-Math.cos(p*Math.PI)/2) + 0.5) * (z.p.x-z.s.l) + z.s.l;

z.scroll(st, sl);

}

};

z.scroll = function (t, l){window.scrollTo(l, t)};

z.timer = window.setInterval(function(){z.step();},13);

}

关键函数
scroller(el, duration)

el : 目标锚点 ID
duration : 持续时间，以毫秒为单位，越小越快
test.html

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
	<head>
		<meta http-equiv="Content-Type" content="text/html; charset=gb2312" />
		<title>test</title>
		<script type="text/javascript" src="test.js"></script>
		<style type="text/css">
div.test {
	width: 400px;
	margin: 5px auto;
	border: 1px solid #ccc;
}

div.test strong {
	font-size: 16px;
	background: #fff;
	border-bottom: 1px solid #aaa;
	margin: 0;
	display: block;
	padding: 5px 0;
	text-decoration: underline;
	color: #059B9A;
	cursor: pointer;
}

div.test p {
	height: 400px;
	background: #f1f1f1;
	margin: 0;
}
</style>

	</head>

	<body>
		<div class="test">
			<a name="header_1" id="header_1"></a>
			<strong onclick="javascript:scroller('header_4', 800);">header_1
				--> header_4</strong>
			<p></p>
		</div>
		<div class="test">
			<a name="header_2" id="header_2"></a>
			<strong onclick="javascript:scroller('header_5', 800);">header_2
				--> header_5</strong>
			<p></p>
		</div>
		<div class="test">
			<a name="header_3" id="header_3"></a>
			<strong onclick="javascript:scroller('header_6', 800);">header_3
				--> header_6</strong>
			<p></p>
		</div>
		<div class="test">
			<a name="header_4" id="header_4"></a>
			<strong onclick="javascript:scroller('header_7', 800);">header_4
				--> header_7</strong>
			<p></p>
		</div>
		<div class="test">
			<a name="header_5" id="header_5"></a>
			<strong onclick="javascript:scroller('header_3', 800);">header_5
				--> header_3</strong>
			<p></p>
		</div>
		<div class="test">
			<a name="header_6" id="header_6"></a>
			<strong onclick="javascript:scroller('header_2', 800);">header_6
				--> header_2</strong>
			<p></p>
		</div>
		<div class="test">
			<a name="header_7" id="header_7"></a>
			<strong onclick="javascript:scroller('header_1', 800);">header_7
				--> header_1</strong>
			<p></p>
		</div>
	</body>
</html>