JSGI (JavaScript Server Gateway Interface) is like a special language that helps different parts of a website talk to each other. Think of it like a big playground where all the different parts of the website can come together and work together.
JSGI helps the different parts of the website talk to each other by following certain rules. It's like when you play a game at school, everyone has to follow the same rules in order to play together.
When someone goes to a website, JSGI helps the website "ask" the server (the big computer that stores all the website's information) for different things, like pictures or videos. JSGI also helps the website "send" information back to the server, like when you fill out a form with your name and email address.
Think of JSGI like a special language that helps different parts of a website talk to each other and work together. Without JSGI, the different parts of the website might not be able to communicate with each other properly and the website might not work as well as it should.