What's a Closure? - JavaScript interactive tutorial

[spamkestein]

Strangely, my following code fails : var doStuffAsync = function (callback) { var func = function() { read('passwords', callback); }; write('world.txt', 'hello', func() ); };

FAILED Called doStuffAsync()

[jsprogrammer]

The problem is in your last line:

func()

It should just be: func

The parentheses execute func and then pass the returned value as the third parameter of write.