// plugin constructor
// accepts two argments, element and options object
function NiceGreeter( element, options ) {
  this.element = $( element );
  this.options = $.extend( true, {}, this.options, options );
  this._init();
}
// defaults for plugin options
NiceGreeter.prototype.options = {
  greeting: 'hello',
  recipient: 'world'
};
// main plugin logic
NiceGreeter.prototype._init = function() {
  var message = this.getMessage();
  this.element.text( message );
};
// getter method
NiceGreeter.prototype.getMessage = function() {
  return this.options.greeting + ' ' + this.options.recipient;
};

// convert constructor to jQuery plugin
$.bridget( 'niceGreeter', NiceGreeter );
// now the constructor can be used as a jQuery plugin
var $elem = $('#elem');
$elem.niceGreeter();
// >> h1 text will be 'hello world'
// set options
$elem.niceGreeter({
  greeting: 'bonjour',
  recipient: 'mon ami'
});
// >> text will be 'bonjour mon ami'
// access constructor instance via .data()
var myGreeter = $elem.data('niceGreeter');