~~~javascript
var u = navigator.userAgent,
ua = navigator.userAgent.toLowerCase();
let isLineApp = u.indexOf("Line") > -1 ? true : false; // Line 內建瀏覽器
let isFbApp = u.indexOf("FBAV") > -1 ? true : false; // FB App 內建瀏覽器

if ((isLineApp || isFbApp) && !window.location.href.includes('openExternalBrowser')) {
var currentUrl = window.location.href;
var redirectUrl = currentUrl.indexOf('?') > -1 ? currentUrl + '&openExternalBrowser=1' : currentUrl + '?openExternalBrowser=1';
window.location.href = redirectUrl;
}
~~~