Add script for the Telegram web interface (#9)

Author: michaelDCurran

TelegramA11yFixes.user.js

@@ -0,0 +1,53 @@
+// ==UserScript==
+// @name           Telegram Accessibility Fixes
+// @namespace      http://axSGrease.nvaccess.org/
+// @description    Improves the accessibility of Telegram.
+// @author         Michael Curran <mick@nvaccess.org>
+// @copyright 2016 NV Access Limited
+// @license GNU General Public License version 2.0
+// @version        2016.1
+// @grant GM_log
+// @include https://web.telegram.org/*
+// ==/UserScript==
+
+function init() {
+	var elem;
+
+	if (elem = document.querySelector(".im_history_messages_peer")) {
+		// Chat history.
+		elem.setAttribute("aria-live", "polite");
+	}
+}
+
+function onNodeAdded(target) {
+	if(target.classList.contains('im_content_message_wrap')) {
+		target.setAttribute("aria-live", "polite");
+	}
+}
+
+function onClassModified(target) {
+}
+
+var observer = new MutationObserver(function(mutations) {
+	for (var mutation of mutations) {
+		try {
+			if (mutation.type === "childList") {
+				for (var node of mutation.addedNodes) {
+					if (node.nodeType != Node.ELEMENT_NODE)
+						continue;
+					onNodeAdded(node);
+				}
+			} else if (mutation.type === "attributes") {
+				if (mutation.attributeName == "class")
+					onClassModified(mutation.target);
+			}
+		} catch (e) {
+			// Catch exceptions for individual mutations so other mutations are still handled.
+			GM_log("Exception while handling mutation: " + e);
+		}
+	}
+});
+observer.observe(document, {childList: true, attributes: true,
+	subtree: true, attributeFilter: ["class"]});
+
+init();

readme.md

@@ -71,3 +71,12 @@ It does the following:
 - Makes day separators in the message history and the about channel pane heading accessible as headings.
 - Reports incoming messages automatically (using a live region).
 - Hides an editable area which isn't shown visually.
+
+### Telegram accessibility fixes
+[Download Telegram Accessibility Fixes](https://github.com/nvaccess/axSGrease/raw/master/TelegramA11yFixes.user.js)
+
+This script improves the accessibility of the [Telegram instant messaging](https://web.telegram.org/) web interface.
+
+It so far does the following:
+
+- Marks the chat history as a live region so new messages are announced automatically.