Check jQuery.
This script should not be not be installed directly. It is a library for other scripts to include with the meta directive // @require https://update.greasyfork.org/scripts/417760/876220/checkJQuery.js
// ==UserScript==
// @name checkJQuery
// @namespace http://www.ocrosoft.com/
// @version 0.100
// @description Check jQuery.
// @author ocrosoft
// @grant unsafeWindow
// ==/UserScript==
// jQuery
var checkJQuery = function() {
let jqueryCdns = [
'http://code.jquery.com/jquery-2.1.4.min.js',
'http://libs.baidu.com/jquery/2.1.4/jquery.min.js',
'http://ajax.aspnetcdn.com/ajax/jQuery/jquery-2.1.4.min.js',
// 可能抽风，多试几次
'http://code.jquery.com/jquery-2.1.4.min.js',
'http://libs.baidu.com/jquery/2.1.4/jquery.min.js',
'http://ajax.aspnetcdn.com/ajax/jQuery/jquery-2.1.4.min.js',
];
function isJQueryValid() {
try {
let wd = unsafeWindow;
if (wd.jQuery && !wd.$) {
wd.$ = wd.jQuery;
}
$();
return true;
} catch (exception) {
return false;
}
}
function insertJQuery(url) {
let script = document.createElement('script');
script.src = url;
document.head.appendChild(script);
return script;
}
function converProtocolIfNeeded(url) {
let isHttps = location.href.indexOf('https://') != -1;
let urlIsHttps = url.indexOf('https://') != -1;
if (isHttps && !urlIsHttps) {
return url.replace('http://', 'https://');
} else if (!isHttps && urlIsHttps) {
return url.replace('https://', 'http://');
}
return url;
}
function waitAndCheckJQuery(cdnIndex, resolve) {
if (cdnIndex >= jqueryCdns.length) {
iLog.e('无法加载 JQuery，正在退出。');
resolve(false);
return;
}
let url = converProtocolIfNeeded(jqueryCdns[cdnIndex]);
iLog.i('尝试第 ' + (cdnIndex + 1) + ' 个 JQuery CDN：' + url + '。');
let script = insertJQuery(url);
setTimeout(function() {
if (isJQueryValid()) {
iLog.i('已加载 JQuery。');
resolve(true);
} else {
iLog.w('无法访问。');
script.remove();
waitAndCheckJQuery(cdnIndex + 1, resolve);
}
}, 100);
}
return new Promise(function(resolve) {
if (isJQueryValid()) {
iLog.i('已加载 jQuery。');
resolve(true);
} else {
iLog.i('未发现 JQuery，尝试加载。');
waitAndCheckJQuery(0, resolve);
}
});
}