How to pass a callback as a parameter into another function

Question

I'm new to ajax and callback functions, please forgive me if i get the concepts all wrong.

Problem: Could i send a callbackfunction as a parameter to another function that will execute the callback?

function firstFunction(){     //some code      //a callback function is written for $.post() to execute     secondFunction("var1","var2",callbackfunction); }  function secondFunction(var1, var2, callbackfunction) {     params={}     if (event != null) params = event + '&' + $(form).serialize();      // $.post() will execute the callback function     $.post(form.action,params, callbackfunction); } 

Answer 1

Yup. Function references are just like any other object reference, you can pass them around to your heart's content.

Here's a more concrete example:

function foo() {     console.log("Hello from foo!"); }  function caller(f) {     // Call the given function     f(); }  function indirectCaller(f) {     // Call `caller`, who will in turn call `f`     caller(f); }  // Do it indirectCaller(foo); // logs "Hello from foo!"

You can also pass in arguments for foo:

function foo(a, b) {     console.log(a + " + " + b + " = " + (a + b)); }  function caller(f, v1, v2) {     // Call the given function     f(v1, v2); }  function indirectCaller(f, v1, v2) {     // Call `caller`, who will in turn call `f`     caller(f, v1, v2); }  // Do it indirectCaller(foo, 1, 2); // logs "1 + 2 = 3"

Answer 2

Also, could be simple as:

if( typeof foo == "function" )     foo();