便捷的全局回到顶部/底部按钮（Top and Down buttons everywhere）
// ==UserScript==
// @name 回到顶部/底部
// @description 便捷的全局回到顶部/底部按钮（Top and Down buttons everywhere）
// @version 1.8-20180308
// @author Max Max
// @license MIT
// @include *
// @icon http://pics.smotri.com/cskins/blue/smiles/bt.gif
// @run-at document-end
// @grant none
// @namespace https://greasyfork.org/users/171855
// @match https://*.baidu.com/*
// @match https://segmentfault.com/*
// @match https://*.v2ex.com/*
// @match https://hacpai.com/*
// @match https://github.com/*
// @match https://*.zhihu.com/*
// @match https://*.cnblogs.com/*
// @match https://*.jianshu.com/*
// @match http://*.163.com/*
// ==/UserScript==
// [1] skip all iframe
if (window.self!=window.top) {
return ;
}
// create element
function ce(n) { return document.createElement(n); } // end of function
// add style
function addStyle(css) {
var head = document.head || document.getElementsByTagName('head')[0];
if (head) {
var style = ce("style");
style.type = "text/css";
style.appendChild(document.createTextNode(css));
head.appendChild(style);
} // end if
} // end of function
// global variables
var position,
// figure out if this is moz || IE because they use documentElement
el = (navigator.userAgent.indexOf('Firefox') != -1 || navigator.userAgent.indexOf('MSIE') != -1) ? document.documentElement : document.body,
// timer
t1, t2,
// speed by
speed_by_click = 200, // edit this value
speed_by_over = 100, // edit this value
// z-index
zIindex = 1001; // edit this value
// move up
function move_up() {
position = document.documentElement.scrollTop || document.body.scrollTop;
window.scrollTo(0, position-1);
t1 = setTimeout(move_up, speed_by_over);
} // end of function
// move downn
function move_dn() {
position = document.documentElement.scrollTop || document.body.scrollTop;
window.scrollTo(0, position+1);
t2 = setTimeout(move_dn, speed_by_over);
} // end of function
// document height
function getDocumentHeight() {
return (document.body.scrollHeight > document.body.offsetHeight)?document.body.scrollHeight:document.body.offsetHeight;
} // end of function
// document scroll
function get_scroll(a) {
var d = document,
b = d.body,
e = d.documentElement,
c = "client" + a,
f = "scroll" + a;
return /CSS/.test(d.compatMode)? (e[c]< e[f]) : (b[c]< b[f]);
} // end of function
// calk
function scrollTo(element, to, duration) {
var //start = element.scrollTop,
start = document.documentElement.scrollTop || document.body.scrollTop,
change = to - start,
currentTime = 0,
increment = 20,
newDuration = (typeof(duration) === 'undefined') ? 500: duration;
var animateScroll = function(){
currentTime += increment;
var val = Math.easeInOutQuad(currentTime, start, change, newDuration);
//element.scrollTop = val;
window.scrollTo(0, val);
if(currentTime < newDuration) { setTimeout(animateScroll, increment); }
};
animateScroll();
} // end of function
//t = current time
//b = start value
//c = change in value
//d = duration
Math.easeInOutQuad = function (t, b, c, d) {
t /= d/2;
if (t < 1) return c/2*t*t + b;
t--;
return -c/2 * (t*(t-2) - 1) + b;
};
// add css
function shareCSS(){
// variables
var s='', img_up, img_dn;
// img vs button
img_up = 'data:img/png;base64,iVBORw0KGgoAAAANSUhEUgAAABIAAAAUCAYAAACAl21KAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsMAAA7DAcdvqGQAAAB+SURBVDhPY1i1atV/amAGahgCMoNhaIGlS5cKAp19BoRBbLJcj2QILDJINwzoAmMgfoclIkBixkS5DI8hMJcRNgxoSBoOl6CnNZBhaVhdBjWE1MSJahjQkA4KEmYH2GUrV66cSYEhYB+AzKBtFiHkQqKiH6Ro1CDCQTWgYQQAs81DU0G/83sAAAAASUVORK5CYII=';
img_dn = 'data:img/png;base64,iVBORw0KGgoAAAANSUhEUgAAABIAAAAUCAYAAACAl21KAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsMAAA7DAcdvqGQAAACPSURBVDhPY2DAAlatWvUfH8amB6vYqEGEg2pgw4iQ7cTKM6xcuXImsYpxqQOZAQ4woIIOCgzrQAl1oEFpZBiWhitFgwx7R4SBIDXYDYGZDFRgTMAwkCHGhBMRJMxwGUa8ITCbli5dKgg08AySN8+AxIhyCboiJMPIN4Qsm6miiYioxltawvSDYogohYTUAQC80UNTOht/YwAAAABJRU5ErkJggg==';
// button id
s+='#play_btn_up { position:fixed; right:0; bottom:53%;z-index:'+zIindex+'; height:36px; width:36px; cursor:pointer; background:url('+img_up+') no-repeat scroll 50% 50% rgba(0, 0, 0, 0.7); border-radius:5px 0 0 5px; margin-top:-24px; }';
s+='#play_btn_dn { position:fixed; right:0; top:53%; z-index:'+zIindex+'; height:36px; width:36px; cursor:pointer; background:url('+img_dn+') no-repeat scroll 50% 50% rgba(0, 0, 0, 0.7); border-radius:5px 0 0 5px; margin-top:-24px; }';
// button class
s+='.play_btn { -webkit-transition-duration:0.5s linear; -o-transition-duration:0.5s linear; -moz-transition-duration:0.5s linear; transition-duration:0.5s linear; opacity:0.65; }';
s+='.play_btn:hover { opacity:1; }';
// append
addStyle(''+s);
} // end of function
// main
function create_btn_element() {
// get scroll
var up, dn,
scrolled,
h = get_scroll('Height');
// exit
if(!h) { return; } // end if
// add css
shareCSS();
// if
if(el){
// create DOM element
up = ce('span');
dn = ce('span');
// set attribute
up.setAttribute('id','play_btn_up');
dn.setAttribute('id','play_btn_dn');
// set class
up.className = "play_btn";
dn.className = "play_btn";
// append element
document.body.appendChild(up);
document.body.appendChild(dn);
// scroll
scrolled = window.pageYOffset || document.documentElement.scrollTop;
// if scroll
up.style.display = (scrolled > 0) ? "" : "none";
// add event over
up.addEventListener('mouseover', move_up, false);
dn.addEventListener('mouseover', move_dn, false);
// add event out
up.addEventListener('mouseout', function(){clearTimeout(t1);},false);
dn.addEventListener('mouseout', function(){clearTimeout(t2);},false);
// add event click
up.addEventListener('click', function(){ scrollTo(el, 0, speed_by_click); }, false);
dn.addEventListener('click', function(){ scrollTo(el, getDocumentHeight(), speed_by_click); }, false);
// add event scroll
window.onscroll = function() {
var scrolled = window.pageYOffset || document.documentElement.scrollTop, diffHeight = document.body.scrollHeight - window.innerHeight;
// if scroll up
up.style.display = (scrolled > 0) ? "" : "none";
// if scroll dn
dn.style.display = (diffHeight > scrolled) ? "" : "none";
}; // end of function
} // end if
} // end of function
// run it
create_btn_element();