// ==UserScript==
// @name        Click To Top
// @namespace    http://tampermonkey.net/
// @version      0.42
// @description  click the arrow-up pic to jump to the top of page.
// @author       kilin
// @include      *
// @match        *
// @grant        none
// @name:zh-CN       点击返回顶部
// @description:zh-CN  点击向上的箭头按钮返回到页面顶部
// ==/UserScript==
(function(){window.onload = function(){
console.log('DOM already loaded.');
if(window.top == window.self){
var aNode = document.createElement('a');
aNode.href = 'javascript:;';
aNode.id = 'click-to-top';
aNode.title = 'Click it to go to the top';
var availHeight = window.screen.availHeight; // 获取可用高度
var css = '#click-to-top{ display:none; position: fixed; right: 5%; bottom: 20%; opacity: 0.2; z-index: 9999; } #click-to-top:hover{ position: fixed; right: 5%; bottom: 20%; opacity: 1; z-index: 9999; }';
//滚出一屏以后才显示返回顶部按钮
window.onscroll = function(){
var curPos = (document.documentElement.scrollTop == 0) ? document.body.scrollTop : document.documentElement.scrollTop; //document.documentElement.scrollTop; //preparation for hack (document.documentElement.scrollTop == 0) ? document.body.scrollTop : document.documentElement.scrollTop;
if(curPos > availHeight){
aNode.style.display = 'block';
}else {
aNode.style.display = 'none';
}
};
//图片相关
var img = document.createElement('img');
img.src = 'https://ooo.0o0.ooo/2017/05/23/59245c636b321.png';
img.style = 'width: 30px; height: 30px;';
//样式相关
var style = document.createElement('style');
if (style.styleSheet) {
style.styleSheet.cssText = css;
} else {
style.appendChild(document.createTextNode(css));
}
document.getElementsByTagName('head')[0].appendChild(style);
aNode.append(img);
aNode.addEventListener('click', function(){
document.body.scrollIntoView();
/*var timer = setInterval(function(){
document.documentElement.scrollTop -= 500;
if(document.documentElement.scrollTop < 100){
clearInterval(timer);
}
}, 50);
}, true);*/
});
var eBody = document.querySelector('body');
eBody.append(aNode);
}
};})();