Code
This works only on the latest Chrome browsers.
When you run this code, you need to allow the browser to use your microphone.
Make sure you turn on your speaker volume, to listen to the response.
Improvements
You can add more accents in speech recognition and audio output, you can also add in more specific speech processing to check the speech for synonyms of commands to be executed. For that purpose I recommend using words.bighugelabs.com as your API endpoint for the synonyms.