// ==UserScript==
// @name         Show English and Chinese Subtitles for Coursera
// @name:zh      于 Coursera 显示中英双字幕
// @name:zh-CN   于 Coursera 显示中英双字幕
// @name:zh-TW   于 Coursera 顯示中英雙字
// @namespace    http://tampermonkey.net/
// @version      0.3
// @description         Show English and Chinese subtitles when you're watching coursera, and you may modify the script mannually as you like
// @description:zh      在 Coursera 显示中英双字幕或手动更改脚本来更换其它语言
// @description:zh-CN   在 Coursera 显示中英双字幕或手动更改脚本来更换其他语言
// @description:zh-TW   于 Coursera 顯示中英雙字或手動更改脚本來更換其他語言
// @author       LouizQ
// @include      http://www.coursera.org/*
// @include      https://www.coursera.org/*
// @grant        none
// @run-at       document-end
// ==/UserScript==
(function() {
'use strict';
//==========================================================================================================
//If you're using high dpi screen, we strongly advise you to add the script:
//若为高分辨率屏幕，我们强烈建议您使用：
//若為高分辨率屏幕，我們强烈建議您使用：
//https://greasyfork.org/scripts/32934-smaller-coursera-subtitle/code/Smaller%20Coursera%20Subtitle.user.js
//or uncomment following stript part to reduce size of coursera subtitle
//或手动取消下面这段脚本的注释，以缩小字幕字号
//或手動取消下面這段脚本的注釋，以縮小字幕字號
/*
var css = 'video::-webkit-media-text-track-display {font-size: 45%;}',
head = document.head || document.getElementsByTagName('head')[0],
style = document.createElement('style');
style.type = 'text/css';
if (style.styleSheet){
style.styleSheet.cssText = css;
} else {
style.appendChild(document.createTextNode(css));
}
head.appendChild(style);
*/
//==========================================================================================================
setInterval(function(){
var video = document.getElementById("c-video_html5_api");
if(video){
var n = video.textTracks;
var bsubtitleoff = true;
for (var o = 0; o < n.length; o++) {
var i = n[o];
if (i.kind !== "subtitles") continue;
if (i.mode == "showing") bsubtitleoff = false;
}
if (!bsubtitleoff) {
for (var o = 0; o < n.length; o++) {
var i = n[o];
//console.log(i.language);
/*
you may delete the double slash above (uncomment it), click save, and refresh coursera webpage to see the language list in console(F12).
你可以删除前一句双斜杠的注释符号，保存并刷新，在控制台（console，F12）中查看有哪些语言。
你可以刪除前一句雙斜杠的注釋符號，保存並刷新，在控制臺（console，F12）中查看有哪些語言。
*/
if (i.kind !== "subtitles") continue;
if (i.language == "zh-CN" || i.language == "zh-TW" || i.language == "en-US" || i.language == "en") {
/*
if you want to change the fixed language, just modify the word in quotation mark as you like
如果你希望更换语言，可以手动修改引号中的内容
如果你希望更換語言，可以手動修改引號中的内容
*/
i.mode = "showing";
} else {
i.mode = "hidden";
}
}
} else {
//warning: you didn't allow to show any subtitles
//字幕未开启//字幕未開啓
}
}
},500);
})();