Question

I try to extend UI dialog according to documentation (UI version 1.8.16):

(function($) {
    $.widget('ui.mydialog', $.extend(true, $.ui.dialog.prototype, {
        _create: function() {
            return $.Widget.prototype._create.apply(this, arguments);
        }
    }));
})(jQuery);

$(function() {
    $('div#dialog').mydialog();
});

Executing of this code causes JS error: “this.uiDialog is undefined”.

And if try to override the _init() method there are no errors, but parent method call takes no effect.

I’m confused.. Which way is legal to extending for e.g. put some custom initialize code?

Answer 1

I think this post would solve your question: Inherit from jQuery UI dialog and call overridden method.

In short, if you want to build a widget inheriting jQuery UI Dialog, you can do this:

(function($) {
    $.widget("ui.mydialog", $.ui.dialog, {
        _create: function() {
            $.ui.dialog.prototype._create.call(this);
        }
    });

})(jQuery);

See this in action: http://jsfiddle.net/william/RELxP/.

---

This tutorial will enlighten you: http://wiki.jqueryui.com/w/page/12138135/Widget%20factory. In short, $.Widget is the base widget object. Even though it has a _create function, it by default does nothing, leaving the initialisation code to the subclass. Take a look at this updated example: http://jsfiddle.net/william/RELxP/1.