jQuery plugin creation and public facing methods

Question

I have created a plugin to convert an HTML select box into a custom drop down using DIV's.

All works well, but i'd like to make it a little better. see my jsFiddle

At the end of the plugin I have 2 methods, slideDownOptions & slideUpOptions, I would like to make these available outside of the plugin so other events can trigger the action.

Im getting a little confused how to do this and more specifically how to call the methods from both within the plugin AND from outside of the plugin.

Any help always appreciated

Answer 1

Think about refactoring your plugin using object oriented code. With this you can make API for your plugins like jQuery UI API. So you could access to plugin methods like:

$('select').customSelect(); // apply plugin to elements
$('select').customSelect('resetOpacity'); // call method resetOpacity();
$('select').customSelect('setOpacity', 0.5); // call method with arguments

Basic template for creating such plugins will look like following:

// plugin example
(function($){
    // custom select class
    function CustomSelect(item, options) {
        this.options = $.extend({
            foo: 'bar'
        }, options);
        this.item = $(item);
        this.init();
    }
    CustomSelect.prototype = {
        init: function() {
            this.item.css({opacity:0.5});
        },
        resetOpacity: function() {
            this.setOpacity('');
        },
        setOpacity: function(opacity) {
            this.item.css({opacity:opacity});
        }
    }

    // jQuery plugin interface
    $.fn.customSelect = function(opt) {
        // slice arguments to leave only arguments after function name
        var args = Array.prototype.slice.call(arguments, 1);
        return this.each(function() {
            var item = $(this), instance = item.data('CustomSelect');
            if(!instance) {
                // create plugin instance and save it in data
                item.data('CustomSelect', new CustomSelect(this, opt));
            } else {
                // if instance already created call method
                if(typeof opt === 'string') {
                    instance[opt].apply(instance, args);
                }
            }
        });
    }

}(jQuery));

// plugin testing
$('select').customSelect();

Working JS fiddle here: http://jsfiddle.net/XsZ3Z/