Add properties and methods to jQuery plugins

jQuery elements are objects so it should be theoretically possible to add methods and properties to them. jQuery plugins work by extending a jQuery object with custom functionalities. They're the perfect place where we can extend a jQuery element object with custom methods and properties.

The object is currently referred by the this keyword. This keyword points to the current element where a plugin is attached to. Knowing this, we can define public methods and properties for our plugin:

(function($) {
    $.fn.plugin = function(options) {

        var self = this;
        var defaults = {
            test: 'Foo',
            bar: 'Baz'
        };

        options = $.extend(defaults, options);


        self.property = 'Test';
        self.method = function() {
            console.log(self.property);
            console.log('Method called');
        }



        return self.each(function() {
            self.property = options.test + ' ' + options.bar;

            $(self).on('click', self.method);

        });
    };
})(jQuery);

We've defined a method and a property. The property's value will be set to both values found in the plugin's options object. The plugin's method will be fired when a user clicks on the attached element.

Our code can either work indirectly on user's click:

$('#test').plugin(); // 'Foo Baz' 'Method called'

or can be called directly like this:

console.log($('#test').plugin().property); // 'Foo Baz'

Being bound to this, our methods and properties work from outside only when the plugin's code has been instantiated. If you try to access them as $(element).plugin.property, you'll get an error. Remember that plugins are basically functions, and functions are first-class citizen JavaScript objects.

You can see the demo on this page.