wikipedia-dark-theme.js

// ==UserScript==
// @name         Wikipedia
// @namespace    http://tampermonkey.net/
// @version      0.1
// @description  try to take over the world!
// @author       You
// @match        https://en.wikipedia.org/*
// @match        https://pt.wikipedia.org/*
// @grant        none
// @import       https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js
// ==/UserScript==

function init() {

    var namesLists = [
            {
                type:   'tag',
                names:  [
                    'html',
                    'pre'
                ]
            },
            {
                type:   'class',
                names:  [
                    'thumbcaption'
                ]
            },
            {
                type:   'id',
                names:  [
                    'mw-panel',
                    'mw-head',
                    'content',
                    'bodyContent',
                    'firstHeading',
                    'footer',
                    'catlinks'
                ]
            }
        ],
        elms    =   []
    ;

    namesLists.map(function(list, i) {

        list.names.map(function(name) {

            switch (list.type) {
                case 'tag':

                    var elmsList     =   document.getElementsByTagName(name);

                    for (var i = 0; i < elmsList.length; i++) {

                        elmsList[i].classList.add('dark-bg');

                    }

                    break;

                case 'class':

                    var elmsList     =   document.getElementsByClassName(name);

                    for (var i = 0; i < elmsList.length; i++) {

                        elmsList[i].classList.add('dark-bg');

                    }

                    break;

                case 'id':

                    document.getElementById(name).classList.add('dark-bg');

                    break;
            }

        });

    });

    var sheet = (function() {

        var style = document.createElement('style');

        // WebKit hack :(
	    style.appendChild(document.createTextNode(''));

        document.head.appendChild(style);

        return style.sheet;

    })();

    sheet.addRule('.dark-bg', 'background-color: #999; color: #f2f2f2;', 0);
    sheet.addRule('a', 'color: #ffffcc', 0);
    sheet.addRule('p, span, h1, h2, h3, h4, h5, h6', 'color: #f2f2f2; -webkit-font-smoothing: antialiased;', 0);
    sheet.addRule('#toc', 'background-color: gray;', 0);
    sheet.addRule('.mw-wiki-logo', 'background-image: url(//upload.wikimedia.org/wikipedia/en/thumb/8/80/Wikipedia-logo-v2.svg/1200px-Wikipedia-logo-v2.svg.png); background-size: contain; width: 7em;', 0);
    sheet.addRule('div#mw-panel', 'width: 11em;', 0);
    sheet.addRule('li span', 'background-image: none; background-color: gray;', 0);
    sheet.addRule('table.plainlinks', 'display: none;', 0);

    var anchorList  =   document.getElementsByTagName('a');

    for (var i = 0; i < anchorList.length; i++) {

        anchorList[i].setAttribute('target', '_blank');

    }

}

init();