jQuery UI 1.10: The User Interface Library for jQuery: Need to learn how to use JQuery UI speedily? Our guide will take you through implementing and customizing each library component in clear, concise steps, all supported by practical examples to make learning faster. , Fourth Edition

This book is specifically tailored towards Version 1.10 of jQuery UI and requires jQuery 1.6 or higher; throughout this book, we will be using jQuery 2.0.3 in our code samples.

To obtain a copy of the library, we should visit the Download Builder at http://www.jqueryui.com/download. This tool gives us a range of different options for building a download package that is tailored to our particular requirements. The following screenshot shows the Download Builder:

We can either download the complete current release or a complete package of a legacy version. We can also select just the components that we want and download a custom package—this is particularly recommended for production environments, where we are only using a subset of the UI library; this helps to reduce bandwidth used when viewing the page.

The page is laid out in a friendly and easy-to-use way. It lists all of the different components in their respective groupings (UI Core, Interactions, and Widgets) and allows us to choose from one of the 24 different predesigned themes (or no theme at all). The page also provides information about the package (including both its compressed and uncompressed size).

We'll look at the different files found within the library in just a moment, but for now we should download the complete library. It will contain everything we need, including the JavaScript and CSS files, as well as any images from the current theme that rely on different components. It even contains the latest version of jQuery itself, so we don't need to worry about downloading this separately.

For now, just use the custom Download link at the top of the page then select Smoothness as the theme on the following page, and then click on Download. We'll look at downloading and using other themes in the next chapter.

The code download that accompanies this book includes a copy of jQuery 2.03 within each chapter's exercise folder. If you need to download a new copy, you can do so—the instructions for downloading a new copy are listed in Appendix, Help and Support.

We'll need a location to unpack the jQuery UI library in order to easily access the different parts of it within our own files. We should first create a project folder, into which all of our example files as well as all of the library, and other associated resources can be saved.

Create a new folder in your C: drive, or your home directory, and call it jqueryui. This will be the root folder of our project and will be the location where we store all of the example files that we'll make over the course of the book.

To unpack the library, you can use Windows Explorer (if working on a PC), or a compression program such as 7-zip. When extracting the library, choose the jqueryui folder that we just created. If you are a Mac user, you may need to copy the contents of the jqueryui-1.10.3.custom folder into the new jqueryui folder we have just created. (We will go through the structure of the jqueryui folder later in this chapter.)

The code examples that we'll be looking at use other resources, mostly images, but occasionally some PHP files too. The accompanying code download available on the Packt Publishing website contains all of the images that we'll be using. You should download this if you can, from http://www.packtpub.com/support/book/user-interface-library-for-jquery. You'll need to create a new folder within the jqueryui project folder and call it img, then unpack all of the images within the image folder in the archive to this new folder.

Once you have unpacked the jqueryui folder and added any additional folders that are required, you will see something similar to the following screenshot—here I've used Chapter 5 as an example, which requires an additional img folder to be created:

The code download also contains all the examples as well as the library itself. These files are provided in the hope that they will be used for reference purposes only. I'd recommend that you follow the examples in the book as you go along, manually creating each file as it is shown, instead of just referring to the files in the code download. The best way to learn code, is to code.

This is all that we need to do, no additional platforms or applications need to be installed and nothing needs to be configured or set up. As long as you have a browser and some kind of code or text editor, everything is in place to begin developing with the library.

There are plenty of editors available, any of which will be fine for use with jQuery UI, if you don't already have a preferred editor—for Windows users, you can try Notepad++ (freely available from http://www.notepad-plus-plus.org), or Sublime Text 2 (shareware, which can be downloaded from http://www.sublimetext.com/2). I would avoid using memory-hungry IDEs, as they tend to facilitate too much of the work and therefore impact on the learning curve when using jQuery UI.

Let's take a moment to look at the structure of the library once it has been unpacked, so that we know where to look for specific utilities and files. This will give us a feel for its composition and structure. Open up the jqueryui folder where we unpacked the library. The contents of this folder should be as follows:

We can see what the structure looks like from the following screenshot:

For the purposes of using jQuery UI, it is sufficient to know that the js and css folders are the ones you will need to use within a production environment; these can be dropped into your site structure as they are, and the relevant compressed files referenced accordingly from within your code.

If however you are using the library in a development capacity, then I would recommend using the development-bundle folder instead; this contains the same code as the individual source files, but in uncompressed format.

Examining the folder structure in detail

For most people, it is not necessary to know how the jQuery UI library is made up; after all, the two key folders to use can simply be dropped in to your site and referenced accordingly. In this case, you may wish to skip this section and move onto Working with ThemeRoller.

If however your skills are more advanced and you want to learn more about the structure of the library, then please read on. I would recommend having a copy of the jQuery downloaded to hand as you work through this section, so that you can get to grips with how the library is made up.

The css folder is used to store the complete CSS framework that comes with the library. In this folder there will be a directory that has the name of the theme we chose when building the download package. Inside this is a single file that contains all of the CSS framework, and a folder that holds all the images used by the theme. We can also store the css files that we will be creating in this css directory.

The js folder contains minified versions of jQuery and the complete jQuery UI library, with all components rolled into one file. In a live project, it is the js and css folders that we'd want to drop into our site.

The index is an HTML file that gives a brief introduction to the library and displays all of the widgets along with some of the CSS classes. If this is the first time you've ever used the library, you can take a look at this file to see some of the things that we'll be working with throughout the course of this book.

The development-bundle directory contains a series of resources to help us develop with the library. It consists of the following subdirectories:

1. A demos folder

2. A docs folder

3. An external folder

4. A themes folder

5. A ui folder

The following screenshot shows how the folder structure should appear:

Also present in the directory are the license files, JSON source files, documents showing the version of the library and its main contributors, and an uncompressed version of jQuery.

The demos folder contains a series of basic examples, showing all of the different components in action. The docs folder contains API documents for each of the different components.

The external folder contains a set of tools that may be of use to developers. They are as follows:

• The globalize plugin

• The jshint plugin

• The mousewheel plugin

• The unit testing suite qunit (consisting of a JavaScript and a CSS file)

The globalize plugin provides localization support to jQuery, and can be used to format strings, dates, and numbers in over 350 cultures. The jshint plugin, a derivative of the jslint plugin, is a tool to detect errors and potential problems in JavaScript code while enforcing your own coding conventions. The mousewheel plugin, designed by Brandon Aaron, adds cross-browser mouse wheel support to your website or online application. The QUnit framework is jQuery's unit testing suite that we can use to run unit tests on our any code that we create.

Tip

For more information on QUnit, go to http://docs.jquery.com/QUnit.

The themes folder contains either the default theme or the theme that was selected during the download builder. Other themes that we download at a later point or themes that we create ourselves can also be stored here.

The ui folder contains the individual and uncompressed source files of each of the different components of the library.

Note

If you select the Stable download option from the main page, you will find that the contents appear different—the Stable download option contains the contents of the development-bundle folder only, and the theme included by default is called Base. This is visually similar to the Smoothness theme we've downloaded in the custom package.

ThemeRoller is a custom tool written in jQuery and PHP. It allows us to visually produce our own custom jQuery UI theme and package it up in a convenient and downloadable archive, which we can then drop into our project with no further coding (other than using the stylesheet in an HTML <link> element, of course).

ThemeRoller, hosted at http://ui.jquery.com/themeroller, was created by Filament Group, Inc., and makes use of a number of jQuery plugins released into the open source community. It can be used to produce themes for jQuery UI 1.10 or the legacy Version 1.9 of jQuery UI.

ThemeRoller is certainly the most comprehensive tool available for creating your own jQuery UI themes. We can very quickly and easily create an entire theme comprised of all the styles needed for targeting the different widgets that make up the library, including the images we'll need.

If you looked at the index.html file a little earlier, the ThemeRoller landing page will be instantly familiar, as it shows all the UI widgets on the page, skinned with the default Smoothness theme.

The ThemeRoller page features an interactive menu on the left that is used to work with the application. Each item within the menu expands to give you access to the available style settings for each part of the widget, such as the Content and Clickable areas, the Header and Content areas of the widget, and other associated things, such as warnings and Error messages.

Here we can create our custom theme with ease and see the changes as soon, as they are applied to the different visible parts of each widget on the page, as shown in the following screenshot:

If you're not feeling particularly inspired while creating a theme, there is also a gallery of pre-configured themes that you can instantly use to generate a fully configured theme. Apart from convenience, the best thing about these pre-selected themes is that when you select one, it is loaded into the left menu. Therefore, you can easily make little tweaks as required.

This is an excellent way to create a visually appealing custom theme that matches the style of your existing site, and is the recommended method for creating custom skins.

Installing and using the new theme is as simple as selecting or creating it. The Download theme button in the above screenshot takes us back to the download builder that has the CSS and images for the new theme integrated into the download package.

If it's just the new theme we want, we can deselect the actual components and just download the theme. Once downloaded, the css folder within the downloaded archive will contain a folder that has the name of the theme. We can simply drag this folder into our own local css folder, and then link to the stylesheet from our pages.

We won't be looking at this tool in much detail in this book. We'll be focusing instead on the style rules that we need to manually override in our own custom stylesheets to generate the desired look of the examples manually.

There are three types of component found within the jQuery UI library, as follows:

Let us take a moment to consider the components that make up each of these categories, beginning with the core components.

The core components consist of:

The core file sets up the construct that all components use to function, and adds some core functionality that is shared by all of the library components, such as keyboard mappings, parent-scrolling, and a z-index manager. This file isn't designed to be used on its own, and exposes no functionality that can be used outside of another component.

The interaction helpers are comprised of the following components:

The interaction helpers add basic mouse-based behaviors to any element; this allows you to create sortable lists, resize elements (such as dialog boxes) on the fly or even build functionality (such as a drag-and-drop based shopping cart).

The higher-level widgets (at the time of writing) include:

The widgets are UI controls that bring the richness of desktop application functionality to the Web. Each of the widgets can be fully customized, appearance and their behavior.

Like jQuery itself, this version of jQuery UI officially supports the current and the previous version of a browser, although the library works fine with older versions of major browsers, including the following: IE7+, Firefox 2+, Opera 9+, Safari 3+, and Chrome 1+.

The widgets are built from semantically correct HTML elements generated as needed by the components. Therefore, we won't see excessive or unnecessary elements being created or used.

The library is as flexible as standard JavaScript. By this, I mean that there is often more than one way of doing the same thing, or achieving the same end. For example, the callback events used in the configuration objects for different components can usually take either references to functions or inline anonymous functions, and use them with equal ease and efficiency.

In practice, it is advisable to keep your code as minimal as possible (which jQuery can really help with anyway). But to make the examples more readable and understandable, we'll be separating as much of the code as possible into discrete modules. Therefore, callback functions and configuration options will be defined separately from the code that calls or uses them.

Throughout this book, we will separate JavaScript and CSS code into separate files; while this is overkill for the purposes of development work, it is advisable for production websites. Scripts that reside in external js files can be cached by the browser for vastly improved loading speeds; those written in-line (that is, directly into a <script> tags) are not cached by the browser.

I'd also just like to make it clear that the main aim throughout the course of this book is to learn how to use the different components that make up jQuery UI. If an example seems a little convoluted, it may be that this is the easiest way to expose the functionality of a particular method or property, as opposed to a situation that we would find ourselves coding for regular implementations.

I'd like to add here that the jQuery UI library is currently going through a rapid period of expansion, bug-fixing, and development. For this release, the jQuery team is focusing on bug-fixing to help make the library as stable as possible. Over the longer term, the jQuery UI team is focusing on complete redesigns of each widget's API, ahead of adding a host of new widgets in future releases, and completing a planned merger with jQuery Mobile.

Like jQuery, the jQuery UI library is licensed under the MIT open source license. This is a very unrestrictive license that allows the creators to take credit for its production and retain intellectual rights over it, without preventing us developers from using the library in any way that we like on any type of site.

The MIT license explicitly states that users of the software (jQuery UI in this case) are free to use, copy, merge, modify, publish, distribute, sublicense, and sell. This lets us do pretty much whatever we want with the library. The only requirement imposed by this license is that we must keep the original copyright and warranty statements intact.

This is an important point to make. You can take the library and do whatever you like with it. You can build applications on top of the library and then sell those applications or give them away for free. You can put the library in embedded systems such as cell phone OSes and sell them. But whatever you do, leave the original text file with John Resig's name present on it. You can also duplicate it word-for-word in the help files or documentation of your application.

The MIT license is very lenient, but because it is not copyrighted itself, we are free to change it. We can therefore demand that the users of our software give attribution to us instead of the jQuery team, or pass off the code as our own.

The license is not there to restrict us in any way and is not the same as the kind of license that comes with software that you might purchase and install on your own computer. In most cases, how the library is licensed will not be a consideration when using it. Plugin authors, however, will want to ensure that their plugins are released under a similar license.

Once you've worked with one of the components from the library, you'll instantly feel at home when working with any of the other components, since the methods of each component are called in exactly the same way.

The API for each component consists of a series of different methods. While these are all technically methods, it may be useful to categorize them based on their particular function.

Methods are consistently called throughout each of the different components by passing the method that we'd like to call, as a simple string to the component's plugin method, with any arguments that the method accepts passed as strings after the method name.

For example, to call the destroy method of the accordion component, we would simply use the following code:

$("#someElement").accordion("destroy");

See how easy that was! Every single method that is exposed by all of the different components is called in this same simple way.

Some methods such as standard JavaScript functions accept arguments that trigger different behavior in the component. If we wanted to call the disable method on a particular tab in the tabs widget for example, we would use the following code:

$("#someElement").tabs("disable", 1);

The disable method, when used in conjunction with the tabs widget, accepts an integer that refers to the index of the individual tab within the widget. Similarly, to enable the tab again we would use the enable method as shown in the following code:

$("#someElement").tabs("enable", 1);

Again, we supply an argument to modify how the method is used. Sometimes the arguments that are passed to the method vary between components. The accordion widget, for example, does not enable or disable individual accordion panels, only the whole widget, so no additional arguments following the method name are required.

The option method is slightly more complex than the other common methods, but it's also more powerful and is just as easy-to-use. The method is used to either get or set any configurable option after the component has been initialized.

To use the option method in getter mode to retrieve the current value of an option, we could use the following code:

$("#someElement").accordion("option", "navigation");

The previous code would return the current value of the navigation option of the accordion widget. So to trigger the getter mode, we just supply the option name that we'd like to retrieve.

In order to use the option method in the setter mode instead, we can supply the option name and the new value as arguments:

$("#someElement").accordion("option", "navigation", true);

The previous code would set the value of the navigation option to true. Note that an object literal can also be passed to the option method in order to set several different options at once. For example:

$("#someElement").accordion("option", {
  animate: "bounceslide",
  heightStyle: "fill"
});

As you can see, although the option method gives us the power to use both the get and set configuration options, it still retains the same easy-to-use format of the other methods.

var options = {
  select: function() {
  ...
  }
};
$("#myTabs").tabs(options);

$("#someElement").on("tabsselect", function() {
...
});

beforeClose: function() {
  if (readyToClose === false) {
    event.preventDefault();
}

$("#myAccordion").accordion({
  activate: function (event, ui) {
    if(ui.newHeader.length > 0){
      alert(ui.newHeader.attr("id"));
    } else {
      // closed
    }
  }
});

jQuery UI removes the difficulty of building engaging and effective user interfaces. It provides a range of components that can be used quickly and easily out of the box with little configuration. Each component exposes a comprehensive set of properties and methods for integration with your pages or applications that can be leveraged if a more complex configuration is required.

Each component is designed to be efficient, lightweight, and semantically correct, all while making use of the latest object-oriented features of JavaScript, and using a concise, well-tested framework. When combined with jQuery, it provides an awesome addition to any web developer's toolkit.

So far, we've seen how the library can be obtained, how your system can be set up to utilize it, and how the library is structured. We've also looked at how we can add or customize a theme for different widgets, how the API simply and consistently exposes the library's functionality, and the different categories of component. We've covered some important topics during the course of this chapter, but now we can get on with using the components of jQuery UI and get down to some proper coding, beginning with a look at the CSS framework.