JavaScript 2.0-The Complete Reference, Second ... - freecodingtutorial

A similar kind of nameless function doesn‘t even get assigned a name at any time. An
anonymous function is one that cannot be further referenced after assignment or use. For
example, we may want to sort arrays in a different manner than what the built-in sort() method
provides (as we‘ll see in Chapter 7); in such cases, we may pass an anonymous function:
var myArray = [2, 4, 2, 17, 50, 8];
myArray.sort( function(x, y)
{
}
);
// function statements to do sort
The creation of an anonymous function is in this case carried out by using a function literal.
While the function is accessible to sort() because it was passed a parameter, the function is
never bound to a visible name, so it is considered anonymous.
Anonymous functions may be confusing, so you probably won‘t need to use them very often, if
at all. Probably the only other place they are used in JavaScript is with event handlers, as
shown here:
Simple Event and Anonymous Function