What are callback functions in Javascript

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Callback functions in JavaScript are functions that are passed as arguments to other functions and are executed at a later point in time. They allow us to control the flow of execution and perform actions asynchronously.

Here is an example of a callback function in JavaScript:

function fetchData(callback) {
// Simulating an asynchronous operation
setTimeout(function() {
const data = 'Some data';
callback(data);
}, 2000);
}
function processData(data) {
console.log('Processing data:', data);
}
fetchData(processData);

In this example, the fetchData function takes a callback function as an argument. It simulates an asynchronous operation using setTimeout and after 2 seconds, it calls the callback function with the fetched data. The processData function is the callback function that receives the data and processes it.

Using HTML format for the answer:

<!DOCTYPE html>
<html>
<head>
<title>Callback Function Example</title>
<script>
function fetchData(callback) {
// Simulating an asynchronous operation
setTimeout(function() {
const data = 'Some data';
callback(data);
}, 2000);
}
function processData(data) {
console.log('Processing data:', data);
}
fetchData(processData);
</script>
</head>
<body>
<h1>Callback Function Example</h1>
<p>Check the browser console for the output.</p>
</body>
</html>

You can save the above code in an HTML file and open it in a web browser to see the output in the browser console.