JQUERY Mobile Overview Norman White

What is JQUERY Mobile? jQuery Mobile is a touch-friendly UI framework built on jQuery Core that works across all popular mobile, tablet and desktop platforms. “jQuery Mobile is a user interface framework based on jQuery that works across all popular phones, tablet, e-reader, and desktop platforms. Built with accessibility and universal access in mind, we follow progressive enhancement and responsive web design (RWD) principles. HTML5 Markup-driven configuration makes it easy to learn, but a powerful API makes it easy to deeply customize the library.” JQUERY Mobile Introduction page

New Additions - data-roles pages and dialogs A page in jQuery Mobile consists of an element with a data- role="page" attribute. Within the "page" container, any valid HTML markup can be used, but for typical pages in jQuery Mobile, the immediate children of a "page" are divs with data- role="header", class="ui-content", and data-role="footer". The baseline requirement for a page is only the page wrapper to support the navigation system, the rest is optional. A page can be styled as a dialog that makes the page look like it's a modal style overlay. To give a standard page the appearance of a modal dialog, add the data-rel="dialog" attribute to the link. Transitions can also be set on dialog links.

Ajax enhancments jQuery Mobile includes an Ajax navigation system to support a rich set of animated page transitions by automatically 'hijacking' standard links and form submissions and turning them into an Ajax request. The back button is fully supported and there are features to prefetch & cache, dynamically inject, and script pages for advanced use cases.

Link and Form interception Whenever a link is clicked or a form is submitted, that event is automatically intercepted by the Ajax navigation system and is used to issue an Ajax request based on the href or form action instead of reloading the page. While the framework waits for the Ajax response, a loader overlay is displayed. Note: This is all done seamlessly by JQUERY Mobile and the user does not realize that the page is being rebuilt on the fly, possibly with content being fetched over the internet.

Page loading and transitions Everything happens without refreshing page When the requested page loads, jQuery Mobile parses the document for an element with the data-role="page" attribute and inserts that code into the DOM of the original page. Next, any widgets in the incoming page are enhanced to apply all the styles and behavior. The rest of the incoming page is discarded so any scripts, stylesheets or other information will not be included. The framework will also note the title of the incoming page to update the title when the new page is transitioned into view. Now that the requested page is in the DOM and enhanced, it is animated into view with a transition. By default, the framework applies a fade transition. To set a custom transition effect, add the data-transition attribute to the link.

Content and Widgets Inside your content container, you can add any standard HTML elements - headings, lists, paragraphs, etc. You can write your own custom styles to create custom layouts by adding an additional stylesheet to the head after the jQuery Mobile stylesheet. jQuery Mobile includes a wide range of touch-friendly UI widgets: form elements, collapsibles, collapsible sets (accordions), popups, dialogs, responsive tables, and much more. For best performance, use the download builder to pick the components you need.

Listviews Puts lists on steroids for easy navigation on a mobile device jQuery Mobile includes a diverse set of common listviews that are coded as lists with a data-role="listview" added. Here is a simple linked list that has a role of listview. We're going to make this look like an inset module by adding a data-inset="true" attribute and we add a dynamic search filter with data-filter="true" and a text field.listviews Acura Audi BMW Cadillac Ferrari

Forms The framework contains a full set of form elements that are automatically enhanced into touch-friendly styled widgets. Here's a slider made with the new HTML5 input type of range, no data-role needed. Be sure to wrap these in a form element and always properly associate a label with every form element.form elements Text Input: Select: One Two Three Input slider:

Responsive Design Automatically adapt to different devices jQuery Mobile has always been designed to work within a responsive web design (RWD) context and our docs and forms had a few responsive elements from the very start. All the widgets are built to be 100% flexible in width to fit easily inside any responsive layout system you choose to build.responsive web design (RWD) The library also includes a number of responsive widgets like responsive grids, reflow tables and column chooser tables, and sliding panels.responsive gridsreflow tables column chooser tablessliding panels

RWD Basics RWD has three key elements: CSS media queries, used to target styles to specific device characteristics such as screen width breakpoint or resolution. A fluid grid, that specifies elements and widgets in flexible units with the goal of making them flow to fill their containers. Flexible images and media, are also sized in relative units so they re-size to fit within their containers.

RWD Allows document to automatically reformat based on size By creating all screen elements to be fluid and flexible, it allows the media queries to focus primarily on controlling layout rules for containers; the modules inside simply re- size to fit their containers. A simple responsive example may be two stacked containers, each with flexible content or widgets inside. At greater widths, media queries are used to float both containers to create a two column layout to take better advantage of the wider screen. Since the content inside each container is designed to re- flow to fit its parent, the media queries can focus just on the rules for making the columns stack or float, and to override or add styles only needed at greater widths.

Progressive Enhancement (built into Jquery) In addition to these three core RWD principles, we advocate following progressive enhancement (PE) practices. This means always starting with semantic HTML which will work on any device, then unobtrusively layering in advanced CSS and JS only for capable browsers. This provides a solid foundation for the device- level optimizations that RWD provides and is how the jQuery Mobile library is built.

Responsive Web Design Tips Create a style override stylesheet and include it after the jQuery Mobile framework stylesheet. This will hold all your custom styles, tweaks to the default widgets and media queries. Start by writing the styles you want to see at the narrowest screen width (i.e. "mobile first"). These should be outside a media query. This mobile-first approach is efficient because you can lay down the core typography, colors and styles for mobile knowing that these tend to also be used for wider breakpoints. Choose the breakpoints based on your content, not a specific device. Since there are devices of every imaginable width, it's smarter to choose breakpoints based on how your content looks in your design system. As you re-size the window to greater widths, identify where your content hits a point where it could adapt to take advantage of a wider width. Write media queries' widths in ems, not pixels. This ensures the layout will adapt to font size changes in addition to screen widths. To calculate the width in ems, divide the target breakpoint in pixels (320px) by 16px (the default font size) to get the em-based width (20em). Use min-width breakpoints that build on top of the mobile styles. The first breakpoint applies layout adjustments on top of the standard mobile styles so these can be fairly lightweight. Additional min-width breakpoints can be added for even wider screens that each build on the previous breakpoint styles. To override framework styles only for smaller screens, use a max-width breakpoint instead. This allows you to constrain your style overrides to only apply below a certain screen width. Above this width, all the normal styles will apply so this is good for certain types of overrides.

Example of RWD build for mobile first /* Start with core styles outside of a media query that apply to mobile and up */ /* Global typography and design elements, stacked containers */ body { font-family: Helvetica, san-serif; } H1 { color: green; } a:link { color:purple; } /* Stack the two content containers */.main,.sidebar { display:block; width:100%; } /* First breakpoint at 576px */ /* Inherits mobile styles, but floats containers to make columns all and (min-width: 36em) {.main { float: left; width:60%; }.sidebar { float: left; width:40%; } } /* Second breakpoint at 800px */ /* Adjusts column proportions, tweaks base H1 all and (min-width: 50em) {.main { width:70%; }.sidebar { width:30%; } /* You can also tweak any other styles in a breakpoint */ H1 { color: blue; font-size:1.2em } }

Theming jQuery Mobile has a robust theme framework that supports up to 26 sets of toolbar, content and button colors, called a "swatch". Just add a data-theme="b" attribute to any of the widgets on this page to turn it black. Cool party trick: add the theme swatch to the page and see how all the widgets inside the content will automatically inherit the theme. When you're ready to build a custom theme, use ThemeRoller to drag and drop, then download a custom theme.

Takeaway JQuery Mobile takes much of the work out of developing a layout that works on a mobile device, and also allows for web pages that automatically adapt to any device size, smartphone, tablet, desktop. Themes allow the developer to choose from a variety of User Interfaces, which they can then customize.