Greasy Fork

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平滑的滚动到顶部/底部

为网页增加滚到顶部和底部按钮

当前为 2015-03-23 提交的版本，查看 最新版本。

// ==UserScript==
// @name	平滑的滚动到顶部/底部
// @author	burningall
// @description	为网页增加滚到顶部和底部按钮
// @version     2015.3.23-2.0
// @include			http://*
// @include			https://*
// @include			ftp://*
// @supportURL		http://www.burningall.com
// @contributionURL	[email protected]|alipay.com
// @namespace http://greasyfork.icu/zh-CN/users/3400-axetroy
// ==/UserScript==

//绑定事件函数
//使用方法：addEvent(ovj,'event',function(){})
function addEvent(obj,event,fn){
	return obj.addEventListener ? obj.addEventListener(event,fn,false) : obj.attachEventListener('on'+event,fn);
}
	  (addEvent(window,'load',function(){
//元素ID选择
//使用方法：$('id')
function $(id){
	return document.getElementById(id)
	}
//获取元素的属性/样式
//使用方法getStyle(对象，"属性")，像素带px
//parseInt(getStyle($("scrollMars"),"width"))获取不带px的数据
function getStyle(obj,attr){
	return obj.currentStyle ? obj.currentStyle[attr]  :getComputedStyle(obj)[attr];
	}

//获取滚动条位置
function getScrollTop(){
	return document.documentElement.scrollTop ? document.documentElement.scrollTop : document.body.scrollTop;
	}
//获取浏览器可见的窗口高度
function getClientHeight(){
	return document.documentElement ? document.documentElement.clientHeight : document.body.clientHeight
}
//获取文档总高度
//scrollTop + clientHeight == scrollHeight
//滚动条高度+浏览器可是区域高度=文档总高度
function getScrollHeight(){
	return document.body ? 　bodyScrollHeight = document.body.scrollHeight : document.documentElement.scrollHeight;
}
//创建元素
//使用方法 createElement("div","demo","width:500px;height:500px",document.documentElement)
function createElement(tagName,idName,styleList,appendPosition){
	var newElement = document.createElement(tagName);//创建元素的标签命
	newElement.id=idName;//设置元素的属性
	newElement.style.cssText=styleList;//设置元素样式
	appendPosition.appendChild(newElement);//插入元素
	}
//元素的属性变化/移动
//使用方法doMove(obj,"left",20,800),对象，属性，速度，目标点
function doMove(obj,attr,dir,target,endFn){
	dir=parseInt(getStyle(obj,attr))<target ? dir : -dir;	//对于方向矫正
	clearInterval(obj.timer)
	obj.timer=setInterval(function(){
		var speed=parseInt(getStyle(obj,attr))+dir	//步长
		if(speed>target&&dir>0 || speed<target&&dir<0){	//判断往前或往后
			speed=target
			}
		obj.style[attr]=speed+"px"	//赋值
		if(speed==target){
			clearInterval(obj.timer)
			endFn &&endFn()	//回掉函数
			}
		},30)
	}
	//创建滚动按钮
	createElement("div", "scrollMars", "width:100px;height:120px;position:fixed;right:20px;top:200px", document.documentElement);	
	scrollMars.innerHTML = "<div id='goTop' class='Top-and-Btn'></div>" + "<div id='goBtn' class='Top-and-Btn'></div>";
	var scrollStyle = "width:40px;height:40px;text-align:center;padding:5px;margin:5px auto;background:#303030;color:#fff;display:block;opacity:0.8;fitter:alpha(opacity:80);cursor:pointer;border-radius:50%;box-shadow:2px 2px 40px 2px #303030;";
	$('goTop').style.cssText = scrollStyle;
	$('goBtn').style.cssText = scrollStyle;
	$('goTop').innerHTML = "顶" + "<br/>" + "部";
	$('goBtn').innerHTML = "底" + "<br/>" + "部";
	//向上滚动
	addEvent($("goTop"), 'click',
	function() {
		clearInterval($("goTop").timer);
		$("goTop").timer = setInterval(function() {
			var speed = (getScrollTop() / 5) + 10;
			position = getScrollTop() - speed;
			if (position <= 0) {
				document.body.scrollTop = document.documentElement.scrollTop = 0;
				clearInterval($("goTop").timer);
				$("goTop").timer=null;
			}
			document.body.scrollTop = document.documentElement.scrollTop = position;
		},
		30)
	})
	//向下滚动
	addEvent($("goBtn"), 'click',
	function() {
		clearInterval($("goTop").timer);
		$("goTop").timer = setInterval(function() {
			var speed = (getScrollTop() / 5) + 10;
			position = getScrollTop() + speed;
			if (position + getClientHeight() >= getScrollHeight()) {
				document.body.scrollTop = document.documentElement.scrollTop = getScrollHeight();
				clearInterval($("goTop").timer);
				$("goTop").timer=null;
			}
			document.body.scrollTop = document.documentElement.scrollTop = position;
		},
		30)
	})
	//鼠标移入与移出
	addEvent($("scrollMars"), 'mouseover',
	function() { //鼠标移入
		doMove($("scrollMars"), 'right', 10, 20,
		function() {
			doMove($("scrollMars"), 'width', 20, 100)
		})
	});
	addEvent($("scrollMars"), 'mouseout',
	function() { //鼠标移出
		doMove($("scrollMars"), 'right', 10, -80,
		function() {
			doMove($("scrollMars"), 'width', 20, 160)
		})
	})
	addEvent($("goTop"), 'mouseover',function(){$("goTop").style.background = "#FF0004";})
	addEvent($("goTop"), 'mouseout',function(){$("goTop").style.background = "#303030";})
	addEvent($("goBtn"), 'mouseover',function(){$("goBtn").style.background = "#FF0004";})
	addEvent($("goBtn"), 'mouseout',function(){$("goBtn").style.background = "#303030";})
		
}))