Trello Card Links User Script https://opensolitude.com/2016/03/01/trello-card-links.html

trello-card-links.user.js

// ==UserScript==
// @name         Trello Card Links
// @namespace    https://opensolitude.com/
// @version      0.2
// @description  Adds support for markdown hyperlink syntax in your Trello card titles.
// @author       Jordan Bach
// @match        https://trello.com/*
// @grant        none
// ==/UserScript==

(function() {
    if (!NodeList.prototype.forEach) NodeList.prototype.forEach = Array.prototype.forEach;
    if (!NodeList.prototype.indexOf) NodeList.prototype.indexOf = Array.prototype.indexOf;

    var dirty = false;

    function renderCardLinks() {
        var cardTitleSel = 'a.list-card-title, h2.window-title-text';
        var markdownUrlPattern = /\[([^\]]+)\]\(([^\)]+)\)/g;

        document.querySelectorAll(cardTitleSel).forEach(function(el) {
            el.innerHTML = el.innerHTML.replace(markdownUrlPattern, function(match, linkText, url) {
                return '<u href="' + url + '">' + linkText + '</u>';
            });
        });
    }

    function needsRender() {
        dirty = true;
    }

    document.addEventListener('blur', function() {
        window.setTimeout(needsRender, 0);
    }, true);

    document.addEventListener('click', function(e) {
        var href = e.target.getAttribute('href');

        if (e.target.nodeName === 'U' && href && href.indexOf('/') !== 0 && e.metaKey) {
            e.preventDefault();
            window.open(href, '_blank');
            e.stopPropagation();
        } else if (e.target.nodeName === 'A' && href.indexOf('/c/') !== -1) {
            window.setTimeout(needsRender, 100);
        }
    }, true);

    document.addEventListener('load', needsRender, true);

    window.setInterval(function() {
        if (dirty) {
            renderCardLinks();
            dirty = false;
        }
    }, 100);
})();