Chat Web App (receive new messages efficiently)

Intro: A chat group to be used by about 10 people simultaneously. For the user to see new messages appear straight away. ** This is actually a simple project. I would like you to demonstrate to me some rows of messages in a database that can appear in the client browser in real-time. You do not need to design an app or anything special. ** Problem: An efficient way of showing new messages without making too many server requests. Imagine nobody sends a message for 3 hours, then there is no need to keep checking the server. Technology being used: Web app (JQuery) on a Windows Server using MS SQL database. The server-side scripts are written in ASP/VBScript (these can be replaced with Node.JS if you wish). What we must have: 1. Web page (to show the messages) 2. Database (with a table storing the messages and date) 3. Server code to get it working (**this is your main task**) Do not want: XHR AJAX request loading every 3 seconds using javascript's "SetInterval" = too mushc waste on the server. Solutions: - AJAX SetInterval 3 seconds (NO) - Long polling (Plan B) - Websocket (Plan A preferable) - Another better way? Reply with your chosen solution and I will hire the best one.