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Back to Top

Scroll Back To Top Button

Verzia zo dňa 16.03.2018. Pozri najnovšiu verziu.

Tento skript by nemal byť nainštalovaný priamo. Je to knižnica pre ďalšie skripty, ktorú by mali používať cez meta príkaz // @require https://update.greatest.deepsurf.us/scripts/39499/259015/Back%20to%20Top.js 

// ==UserScript==
// @name         Back to Top
// @namespace    https://github.com/maijz128
// @version      0.2
// @description  Scroll Back To Top Button
// @author       MaiJZ
// @grant        none
// ==/UserScript==


(function () {
    'use strict';

    const BUTTON_ID = "btnBackToTop";
    const TOP_FUNCTION_NAME = "btnBackToTop_TopFunction";

    addButtonStyle();
    addFunction();
    addButton();

    function addButtonStyle() {
        var style = '#' + BUTTON_ID + '{';
        style += 'display:none; position:fixed; bottom:20px; right:30px; z-index:99; ';
        style += 'font-size:15px; border:0; outline:0; background-color:#fff; color:#8590a6; ';
        style += 'cursor:pointer; text-align: center; width: 40px; height: 40px; ';
        style += 'border-radius:4px; box-shadow:0 1px 3px rgba(26,26,26,.1); ';
        style += '}';

        style += '#' + BUTTON_ID + ':hover { background-color: #d3d3d3;  }';

        addStyle(style);
    }

    function addFunction() {
        window.addEventListener("scroll", function () {
            var minScrollTop = 50;
            if (document.body.scrollTop > minScrollTop || document.documentElement.scrollTop > minScrollTop) {
                document.getElementById(BUTTON_ID).style.display = "block";
            } else {
                document.getElementById(BUTTON_ID).style.display = "none";
            }
        });

        var strFun = 'function ' + TOP_FUNCTION_NAME + '()';
        // strFun += '{ document.body.scrollTop = 0; document.documentElement.scrollTop = 0;}';
        strFun += '{ var scrollHeight = document.documentElement.scrollHeight || document.body.scrollHeight;';
        strFun += 'var increment = scrollHeight / 100;';
        strFun += 'var gotoTop= function(){ var currentPosition = document.documentElement.scrollTop || document.body.scrollTop;';
        strFun += 'currentPosition -= increment; if(currentPosition>0){window.scrollTo(0,currentPosition)}else{window.scrollTo(0,0);clearInterval(timer);timer = null}}; ';
        strFun += 'var timer=setInterval(gotoTop,1); }';

        var elScript = document.createElement("script");
        elScript.innerHTML = strFun;
        document.head.appendChild(elScript);
    }

    function addButton() {
        var strSVG = '<svg class="" title="Back to Top" fill="#8590a6" viewBox="0 0 24 24" width="24" height="24">';
        strSVG += '<path d="M16.036 19.59a1 1 0 0 1-.997.995H9.032a.996.996 0 0 1-.997-.996v-7.005H5.03c-1.1 0-1.36-.633-.578-1.416L11.33 4.29a1.003 1.003 0 0 1 1.412 0l6.878 6.88c.782.78.523 1.415-.58 1.415h-3.004v7.005z"></path></svg>';


        var elButton = document.createElement("button");
        elButton.setAttribute('id', BUTTON_ID);
        elButton.setAttribute("onclick", TOP_FUNCTION_NAME + '()');
        elButton.setAttribute('title', "Back to Top");
        elButton.innerHTML = strSVG;

        document.body.appendChild(elButton);
    }


    function addStyle(styleContent) {
        var elStyle = document.createElement("style");
        elStyle.innerHTML = styleContent;
        document.head.appendChild(elStyle);
    }
})();