What's the meaning of “()” in a function call?

Question

Now, I usually call a function (that requires no arguments) with () like this:

myFunction(); //there\'s empty parens

Except in

Answer 1

Your jQuery bind example is similar to setTimeout(monitor, 100);, you are passing a reference of a function object as an argument.

Passing a string to the setTimeout/setInterval methods should be avoided for the same reasons you should avoid eval and the Function constructor when it is unnecessary.

The code passed as a string will be evaluated and run in the global execution context, which can give you "scope issues", consider the following example:

// a global function
var f = function () {
  alert('global');
};

(function () {
  // a local function
  var f = function() {
    alert('local');
  };

  setTimeout('f()', 100); // will alert "global"
  setTimeout(f, 100);     // will alert "local"
})();

The first setTimeout call in the above example, will execute the global f function, because the evaluated code has no access to the local lexical scope of the anonymous function.

If you pass the reference of a function object to the setTimeout method -like in the second setTimeout call- the exact same function you refer in the current scope will be executed.