The mobile device revolution has placed new demands on web applications. Mobile devices generally have lower bandwidth and lower CPU capacity, forcing us to avoid large complex code. Fortunately, the mobile space has a greater percentage of users running modern browsers than on desktops, so it is feasible to write similar applications with much less code when targeting mobile browsers. However, dealing with the multitude of different platforms is non-trivial, and creating appropriately small packages of code for mobile devices, while still providing sufficient capability for older desktop browsers can be challenging. While there are different ways to deal with platform discrepancies, the hard lessons of the last decade have shown that feature detection is the mechanism for branching.

Fortunately, Dojo 1.7 has evolved with a powerful new feature detection infrastructure. Dojo now uses the popular has() pattern for feature detection in combination with a has()-aware build system. While it is easy enough to write feature detection tests with ad-hoc JavaScript expressions, the has() pattern defines a specific syntax such that the build system can detect these feature-based branches, and one can create application builds that are highly optimized for specific devices, with known feature shims factored out.

One of the most important parts of creating an effective and intuitive user interface on touch-enabled smartphones has nothing to do with visual appearance—instead, it has to do with creating an interface that properly responds to user input based on touch. For Web applications, this means replacing mouse events with touch events. In Dojo 1.7, new touch APIs help make this process easy.

This is an updated version of the post Touching and Gesturing on the iPhone, published in 2008.

dojox.app is a small application framework providing a set of classes to manage the lifecycle and behavior of a single page application hosted on mobile or desktop platforms. The main class, Application, is responsible for managing the lifecycle of the application and is designed to be easily modified with additional custom behaviors. An Application instance contains Scene objects and View objects which provide the visible user interface. The available views, scenes, module dependencies, and other information about the application are all passed into the Application class using a JSON configuration file (by convention).

Dojo 1.7 includes a rewrite of the event handling system and introduces a new module, dojo/on, to provide lighter-weight, faster, more succinct, and more direct event handling. The new event system is highly optimized for mobile applications, with a lightweight footprint and cross-platform touch event normalization. While Dojo continues to provide backwards compatibility with dojo.connect, the dojo/on module eliminates much of code that is rarely used in dojo.connect and can be loaded in 5.2KB minified, half the size of dojo.connect, and fires non-native events twice as fast. The dojo/on module also includes new functionality for extension events, dispatching events, and providing a base class/mixin for adding event emitting functionality to classes. In addition, there is now a new on() method for NodeLists (the results of dojo.query()) based on the new event listening with event delegation.