make edits to a chat web app built with JS, PHP,AJAX

There is a basic chat app built with PHP,JS,Ajax. However it is not responive and aso lakes a few things. the task at hand is to add the following : - always scroll to the latest message withouthaving to manually scroll down - sound notifications when a new message is received on web and on mobile (vibrate). The user should be able to toggle this on and off. - add emojies (using [login to view URL]) - allow user to send picture and video messages and even attachments