JavaScript Patterns 4.6 Immediate Object Initialization

( {

    // here you can define setting values

    // a.k.a. configuration constants

    maxwidth : 600,

    maxheight : 400,

    // you can also define utility methods

    gimmeMax : function() {

        return this.maxwidth + "x" + this.maxheight;

    },

    // initialize

    init : function() {

        console.log(this.gimmeMax());

        // more init tasks...

    }
}).init(); 

Usage

protect the global namespace while performing the one-off initialization tasks. 

Note

If you want to keep a reference to the object after it is done, you can easily achieve this by adding return this; at the end of init().