The event loop is a fundamental part of the JavaScript runtime environment that allows it to handle multiple events and operations concurrently. It is responsible for managing the flow of execution and scheduling events and functions.

When a JavaScript program executes an event-driven function, such as a callback or an asynchronous operation, the event loop starts by adding the function to its task queue. The task queue contains all the functions that need to be executed at some point in the future.

As new events arrive, the event loop checks if any of them are ready to execute immediately. If so, it takes the function from the task queue and schedules it for immediate execution.

If no functions are ready to execute immediately, the event loop continues to poll for new events. When a new event arrives, it adds the corresponding function to the task queue and schedules it for future execution.

The event loop also handles timeouts and other timing-related events by periodically checking the task queue and executing any functions that are scheduled to run at a specific time.

Overall, the event loop is a critical component of JavaScript's runtime environment that allows it to handle multiple events and operations concurrently, making it an essential part of modern web development.