expose term instance to window for programatic use cases (#131)

* expose term to window for programatic use cases

* add a brief introduction about the exposed window.term variable

README.md

@@ -118,6 +118,7 @@ Then open <http://localhost:8080> with a browser, you will get a bash shell with
 - If you want to login with your system accounts on the web browser, run `ttyd login`.
 - You can even run a none shell command like vim, try: `ttyd vim`, the web browser will show you a vim editor.
 - Sharing single process with multiple clients: `ttyd tmux new -A -s ttyd vim`, run `tmux new -A -s ttyd` to connect to the tmux session from terminal.
+- You can access underlying XTerm instance by calling `window.term` in browser, which allows you to interact with the term such as getting a snapshot of terminal content by `term.selectAll(); var terminalContent = term.getSelection().trim();`.
 
 ## Browser Support
 

html/js/app.js

@@ -247,7 +247,9 @@ var openWs = function() {
             term.destroy();
         }
 
-        term = new Terminal({
+        // expose term handle for some programatic cases
+        // which need to get the content of the terminal
+        term = window.term = new Terminal({
             fontSize: 13,
             fontFamily: '"Menlo for Powerline", Menlo, Consolas, "Liberation Mono", Courier, monospace',
             theme: {