Question

So, we should all know about the jQuery document-ready handler:

$(function () {
  // stuff here
});

So basically, if the first parameter for the $ function is a function, then we run it on document startup, right?

Then why won’t this work?

$(foo());

Answer 1

When you type $(foo()); you are actually calling foo and pass the result to $. If you want to use foo as a callback, you need to type $(foo).