2.2 Callbacks

Using Callbacks is one way to implement asynchronous programming in Javascript. A callback is a function that is passed to another function and executes when some condition is met. As a simple example, say we want make a function that asks for the user's name and then greets the user:

function greeting(name) {
	alert('Hello ' + name);
}
function processUserInput(callback) {
	var name = prompt('Please enter your name.');
	callback(name);
}
processUserInput(greeting);