YouTube - Button Container (@require)

Creates a button container, under the video, onto which buttons can be added

Script này sẽ không được không được cài đặt trực tiếp. Nó là một thư viện cho các script khác để bao gồm các chỉ thị meta // @require https://update.greasyfork.org/scripts/2104/5493/YouTube%20-%20Button%20Container%20%28%40require%29.js 

// ==UserScript==
// @name          YouTube - Button Container (@require)
// @namespace     http://userscripts.org/users/23652
// @description   Creates a button container, under the video, onto which buttons can be added
// @include       http://*.youtube.com/*
// @include       http://youtube.com/*
// @include       https://*.youtube.com/*
// @include       https://youtube.com/*
// @copyright     JoeSimmons
// @version       1.0.2
// @license       LGPL version 3 or any later version; http://www.gnu.org/copyleft/lgpl.html
// @grant         GM_addStyle
// ==/UserScript==

/* CHANGELOG

    1.0.2 (1/15/2014)
        - changed license to LGPL
        - updated style
        - added a test mode, so I can work on visual changes more easily
        - modified the main function to return the created button

    1.0.1 (12/13/2013)
        - slight tweak for more flexible styles
            buttons now have a special class which you can modify.
            you can even put buttons outside of the container with
            that class, and they will have that style applied

    1.0.0 (12/13/2013)
        - created

*/

var addButtonToContainer = (function () {
    'use strict';

    var rYoutubeWhitelistedUrls = /^https?:\/\/([^\.]+\.)?youtube\.com\/(watch|user\/|channel\/)/;

    var TEST_MODE = true; // if true, will replace the current style with this one

    // helper functions - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
    function addStyle(contents) {
        var head = document.head || query('html > head'),
            style = document.createElement('style');

        style.id = 'underMovieDivStyle';
        style.type = 'text/css';
        style.appendChild( document.createTextNode(contents) );

        if (head) {
            head.appendChild(style);
        }
    }
    function id(name) {
        return document.getElementById(name);
    }
    function query(name) {
        return document.querySelector(name);
    }
    // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

    function waitForHeadReady() {
        if ( document.head || query('html > head') ) {
            window.setTimeout(handleStyleCreation, TEST_MODE === true ? 3000 : 0);
        } else {
            window.setTimeout(waitForHeadReady, 200);
        }
    }

    function handleStyleCreation() {
        var umdv = id('underMovieDivStyle'),
            obs = new MutationObserver(function (mutations) {
                mutations.forEach(function (mutation) {
                    if (mutation.target.id === 'underMovieDivStyle') {
                        handleStyleCreation();
                    }
                });
            });

        if (TEST_MODE === true || !umdv) {
            if (umdv) {
                umdv.parentNode.removeChild(umdv);
            }

            addStyle('' +
                '#under-movie-div { ' +
                    'background: transparent !important; ' +
                    'display: block; ' +
                    'padding-top: 4px; ' +
                    'padding-bottom: 8px; ' +
                    'text-align: left; ' +
                    'z-index: 999999; ' +
                '}\n\n' +
                '.under-movie-div-button { ' +
                    'background-image: linear-gradient(to top, #F6F6F6 0px, #FCFCFC 100%) !important; ' +
                    'border: 1px solid #CCCCCC; ' +
                    'border-radius: 2px; ' +
                    'color: #666666 !important; ' +
                    'font-size: 12px !important; ' +
                    'font-family: arial, sans-serif !important; ' +
                    'font-weight: 400 !important; ' +
                    'height: auto !important; ' +
                    'line-height: 20px !important; ' +
                    'margin-right: 6px; ' +
                    'padding: 2px 10px !important; ' +
                '}\n\n' +
                // - - - - - - - - - - - - - - - - - - -
                '#watch7-headline { ' +
                    'padding: 4px 0 !important; ' +
                '}\n\n' +
                '#watch7-headline h1 { ' +
                    'text-align: center; ' +
                    'width: 100%; ' +
                '}\n\n' +
                '#upsell-video { ' +
                    'overflow: visible !important; ' + // allow the button container to show on non-video pages
                '}' +
            '');

            // observe the style for changes if test mode enabled
            if (TEST_MODE === true) {
                obs.observe(id('underMovieDivStyle'), {
                    childList : true,
                    attributes : true,
                    characterData : true
                });
            }
        }
    }

    function handleContainerCreation() {
        var holder = query('#watch7-headline, #gh-overviewtab div.c4-spotlight-module-component'),
            container = id('under-movie-div');

        if (container == null) {
            container = document.createElement('div');
            container.id = 'under-movie-div';

            if (holder) {
                holder.appendChild(container);
            }
        }

        return container;
    }

    function add(text, onclick, ID) {
        var upsellVideo = id('upsell-video'),
            container = handleContainerCreation(),
            button = document.createElement('button'),
            span = document.createElement('span');
            ID = ID || text.replace(/[^a-zA-Z0-9-_]/, '');

        if ( !location.href.match(rYoutubeWhitelistedUrls) || id(ID) ) { return; }
        if (typeof text !== 'string' || typeof onclick !== 'function') { return; }

        span.setAttribute('class', 'yt-uix-button-content');
        span.appendChild( document.createTextNode(text) );

        button.id = ID;
        button.addEventListener('click', function () {
            window.setTimeout(onclick, 0);
        }, false);

        button.type = 'button';
        button.setAttribute('class', 'under-movie-div-button yt-uix-button yt-uix-button-text yt-uix-tooltip');
        button.appendChild(span);

        return container.appendChild(button);
    }

    waitForHeadReady();

    return add;
}());

/* EXAMPLE BUTTON
    addButtonToContainer('A Test Button', function () { alert('Test.'); }, 'test-button');
*/