Connect to Socket.io from the browser app

- [Instructor] We are able to send requests…from the client or browser to Node,…but there is no way to do it in reverse.…There's no way for Node to tell one or more clients,…hey, there's a new message,…so the only way to achieve this behavior…with HTTP requests is to do something called polling.…With polling, every few seconds we send…an HTTP request asking the server,…hey, are there any updates?…Are there new messages I should display?…And we check over and over.…It would be much better…if the server could just tell the client…when a new message comes in…without the clients having to constantly check.…

You can think of it as a bunch…of kids in a van asking the parents every minute,…hey, are we there yet?…The parents might plead with the kids…to stop asking at one point,…and that they will tell the kids…when they arrive instead of them asking.…This is how WebSockets work…and we will be using a WebSocket library called Socket.IO…that works for both the browser and for Node.…With Socket.IO, we will be able to notify clients…