Spring blog hide sidebar greasemonkey script

Spring Blog cleanup.user.js

// ==UserScript==
// @name         Spring Blog cleanup
// @namespace    http://tampermonkey.net/
// @version      0.1
// @description
// @author       You
// @match        https://spring.io/blog/*
// @grant        none
// ==/UserScript==

(function() {
    'use strict';

    var showing = true;
    var documentationWidthBeforeHiding;
    var hideNavIcon = 'data:image/svg+xml;base64,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';
    var showNavIcon = 'data:image/svg+xml;base64,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';

    var toggle = document.createElement('img');
    toggle.src = hideNavIcon;
    toggle.style.position = 'fixed';
    toggle.style.bottom = "10px";
    toggle.style.right = "10px";
    toggle.style.width = "20px";
    toggle.style.height = "20px";
    toggle.style.cursor = "pointer";
    toggle.addEventListener("click", function() {
        showing = !showing;
        if (!showing) {
            hideNav();
        } else {
            showNav();
        }
    });
    document.getElementsByTagName('body')[0].appendChild(toggle);

    function hideNav() {
        console.log('hiding sidebar');
        var sidebar = document.getElementById('sidebar');
        sidebar.style.display = 'none';
        var mainContent = document.getElementById('content');
        removeClass(mainContent, 'span8');
        addClass(mainContent, 'span12');
        toggle.src = showNavIcon;
    }

    function showNav() {
        console.log('showing controls');
        var sidebar = document.getElementById('sidebar');
        sidebar.style.display = '';
        var mainContent = document.getElementById('content');
        removeClass(mainContent, 'span12');
        addClass(mainContent, 'span8');
        toggle.src = hideNavIcon;
    }

    function hasClass(el, className) {
        if (el.classList)
            return el.classList.contains(className);
        else
            return !!el.className.match(new RegExp('(\\s|^)' + className + '(\\s|$)'));
    }

    function addClass(el, className) {
        if (el.classList)
            el.classList.add(className);
        else if (!hasClass(el, className)) el.className += " " + className;
    }

    function removeClass(el, className) {
        if (el.classList)
            el.classList.remove(className);
        else if (hasClass(el, className)) {
            var reg = new RegExp('(\\s|^)' + className + '(\\s|$)');
            el.className=el.className.replace(reg, ' ');
        }
    }
})();