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Scroll Up

Tool to let you scroll to the top of the page

当前为 2017-08-28 提交的版本，查看 最新版本。

// ==UserScript==
// @name         Scroll Up
// @namespace    
// @version      0.1
// @description  Tool to let you scroll to the top of the page
// @author       A Meaty Alt
// @exclude      https://fairview.deadfrontier.com/onlinezombiemmo/index.php?page=21
// @include      /fairview.deadfrontier.com/
// @require      http://code.jquery.com/jquery-1.12.4.min.js
// @grant        none
// ==/UserScript==

(function() {
    'use strict';
    var scroller = document.createElement("img");
    scroller.src = "https://puu.sh/xluRH/c8dd354a59.png";
    scroller.id = "scroller";
    scroller.style.opacity = 0.3;
    scroller.style.position = "fixed";
    scroller.style.zIndex = 99;
    scroller.style.cursor = "pointer";
    scroller.style.bottom = "30px";
    scroller.style.right = "20px";
    scroller.height = 100;
    scroller.width = 100;
    
    function defineOnClickEvent(){
        $(scroller).click(function() {
            $("html, body").animate({ scrollTop: 0 }, "slow");
            return false;
        });
    }
    
    function defineOnScrollEvent(){
        $(document).scroll(function() {
            if($(window).scrollTop() === 0) {
                $("#scroller").css("opacity", 0.3);
            }
            else
                $("#scroller").css("opacity", 1);
        });
    }
    defineOnScrollEvent();
    defineOnClickEvent();
    
    document.getElementsByTagName("body")[0].appendChild(scroller);
})();