JavaScript provides built-in functions to execute code after a specified time delay or at regular intervals.

1. setTimeout(callbackFunction, delayInMilliseconds, arg1, arg2, ...): Executes callbackFunction once after the delayInMilliseconds has passed. Any additional arguments (arg1, arg2, etc.) are passed to the callback function. setTimeout returns a timer ID, which can be used with clearTimeout() to cancel the timer before it executes.

function greetLater() {
  console.log("Hello after 2 seconds!");
}

let timerId = setTimeout(greetLater, 2000); // 2000 milliseconds = 2 seconds

// To cancel:
// clearTimeout(timerId);

// Using an anonymous function and arguments:
setTimeout(function(name) {
  console.log("Hello, " + name + ", after 3 seconds!");
}, 3000, "Developer");

2. setInterval(callbackFunction, intervalInMilliseconds, arg1, arg2, ...): Repeatedly executes callbackFunction with a fixed time intervalInMilliseconds between each call. setInterval also returns a timer ID, which can be used with clearInterval() to stop the repeated execution.

let count = 0;
function showCount() {
  count++;
  console.log("Count: " + count);
  if (count >= 5) {
    clearInterval(intervalId); // Stop after 5 executions
    console.log("Interval stopped.");
  }
}

let intervalId = setInterval(showCount, 1000); // Execute every 1 second

Both setTimeout and setInterval are asynchronous, meaning they don't block the execution of other JavaScript code. The JavaScript engine schedules the callback to run after the delay/interval, but continues processing other tasks in the meantime.