Request / Response

The user’s computer is the client, and their browser takes that address or link and uses it to create an HTTP Request—a request for data sent following the HyperText Transfer Protocol. This request is like a letter asking for information, and is sent to a different computer: the web server that contains that information.

The web server will receive this request, and based on its content (e.g., the parameters of the URL) will decide what information to send as a response to the client. In general, this response will be made up of lots of different files: the text content of the web page, styling information (font, color) for how it should look, instructions for responding to user interaction (button clicks), images or other assets to show, and so forth.