// ==UserScript==
// @name         PTT 404 Redirect to PTTWeb
// @namespace    https://github.com/livinginpurple
// @version      2023.01.31.01
// @description  PTT 網頁 404 的時候 導頁到 PTTWeb
// @license      WTFPL
// @author       livinginpurple
// @match        https://*.ptt.cc/*
// @run-at       document-start
// @grant        none
// @grant        GM.xmlHttpRequest
// ==/UserScript==
(function() {
'use strict';
const scriptName = GM_info.script.name;
console.log(`${scriptName} is loading.`);
function urlExists(url, callback) {
fetch(url, { method: 'head' })
.then(function (status) {
callback(status.ok)
});
}
let url = document.location.href;
urlExists(url, function (exists) {
if (exists) {
// it exists, do something
} else {
location.href = url.replace('ptt', 'pttweb');
}
});
console.log(`${scriptName} is running.`);
})();