How to communicate with an Arduino circuit using a web app?

I have recently made a Arduino circuit as shown in the link below: http://ift.tt/1RO56uq

As you can see, the person in the video of the above link used a bluetooth controller app to control and send signals to the Arduino board via HC-05 bluetooth board.

Here's the question. How can I use a web app/ web instead of a native app(like the video) to control and send signals to the Arduino board?