Javascript – Getting a better understanding of callback functions in JavaScript


I understand passing in a function to another function as a callback and having it execute, but I'm not understanding the best implementation to do that. I'm looking for a very basic example, like this:

var myCallBackExample = {
    myFirstFunction : function( param1, param2, callback ) {
        // Do something with param1 and param2.
        if ( arguments.length == 3 ) {
            // Execute callback function.
            // What is the "best" way to do this?
    mySecondFunction : function() {
        myFirstFunction( false, true, function() {
            // When this anonymous function is called, execute it.

In myFirstFunction, if I do return new callback(), then it works and executes the anonymous function, but that doesn't seem like the correct approach to me.

Best Solution

You can just say


Alternately you can use the call method if you want to adjust the value of this within the callback. newValueForThis);

Inside the function this would be whatever newValueForThis is.