Reference: http://rosettacode.org/wiki/Conway%27s_Game_of_Life

conways.js

var game = exports;

game.of = {};
game.of.life = function () {
    var self = this;

    self.init = function ( turns, width, height ) {
        self.board = new Array( height );

        for ( var x = 0; x < height; x++ ) {
            self.board[x] = new Array( width );        

            for ( var y = 0; y < width; y++ ) {
                self.board[x][y] = Math.round( Math.random() );    
            }
        }

        self.turns = turns;
    };   
    
    self.nextGen = function () {
        var boardHeightSize = self.board.length;

        self.nextBoard = new Array( boardHeightSize );    

        for ( var i = 0; i < boardHeightSize; i++ ) {
            var boardWidthSize = self.board[i].length;

            self.nextBoard[i] = new Array( boardWidthSize );
        }

        for ( var x = 0; x < boardHeightSize; x++ ) {
            var boardWidthSize = self.board[x].length;

            for ( var y = 0; y < boardWidthSize; y++ ) {
                var n = 0;
                for ( var dx = -1; dx <= 1; dx++ ) {
                    for ( var dy = -1; dy <= 1; dy++ ) {
                        if ( dx === 0 && dy === 0 ) {
                        } else if (
                            typeof (
                                self.board[x+dx] 
                            ) !== 'undefined' &&

                            typeof (
                                self.board[x+dx][y+dy]
                            ) !== 'undefined' &&

                            self.board[x+dx][y+dy]
                        ) {
                           n += 1; 
                        }
                    }
                }

                var cell = self.board[x][y];

                switch (n) {
                    case 0:
                    case 1:
                        cell = 0;
                        break;
                    case 2:
                        break;
                    case 3:
                        cell = 1;
                        break;
                    default:
                        cell = 0;
                };

                self.nextBoard[x][y] = cell;
            }    
        }

        self.board = self.nextBoard.slice();
    };

    self.print = function () {
        var boardHeigthSize = self.board.length;

        for ( var x = 0; x < boardHeigthSize; x++ ) {
            var boardWidthSize = self.board[x].length,
                seed = '';    

            for ( var y = 0; y < boardWidthSize; y++ ) {
                if ( self.board[x][y] ) {
                    seed += '.';    
                } else {
                    seed += ' ';    
                }
            }

            console.log( seed );
        }    
    };

    self.start = function () {
        setInterval(function () {
            self.print();    
            self.nextGen();
        }, 1200);
    };
};

var gen = new game.of.life();
    gen.init(1000, 20, 20);
    gen.start();