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JavaScript - Self Invoking Functions

Function expressions can be made "self-invoking". A self-invoking expression is invoked (started) automatically, without being called. Function expressions will execute automatically if the expression is followed by (). You have to add parentheses around the function to indicate that it is a function expression.

Recursion is a technique for iterating over an operation by having a function call itself repeatedly until it arrives at a result. Most loops can be rewritten in a recursive style, and in some functional languages this approach to looping is the default. 


// we wrap the function in parentheses to indicate that it a function expression!
(function ()
{
    var x = "Hello!!"; // I will invoke myself
})
(); // Function expressions will execute automatically if the expression is followed by ().
// The function above is actually an anonymous self-invoking function (function without name).