You are previewing HTML5 and JavaScript Web Apps.

HTML5 and JavaScript Web Apps

Cover of HTML5 and JavaScript Web Apps by Wesley Hales Published by O'Reilly Media, Inc.
  1. HTML5 and JavaScript Web Apps
  2. Preface
    1. Who This Book Is For
    2. Who This Book Is Not For
    3. What You’ll Learn
    4. About the Code
    5. Conventions Used in This Book
    6. Using Code Examples
    7. Safari® Books Online
    8. How to Contact Us
    9. Acknowledgments
  3. 1. Client-Side Architecture
    1. Before HTML5
    2. More Code on the Client
    3. The Browser as a Platform
    4. Conclusion
  4. 2. The Mobile Web
    1. Mobile First
    2. Deciding What to Support
      1. Mobile Web Browsers
    3. Mobile Browser Market Share
    4. Browser Grading
    5. HTML5 in the Enterprise
      1. Graceful Degradation
    6. QA and Device Testing
  5. 3. Building for the Mobile Web
    1. Mobile Web Look and Feel
      1. The Look
      2. The Feel
    2. Interactions and Transitions
      1. Sliding
      2. Flipping
      3. Rotating
      4. Debugging Hardware Acceleration
      5. Memory Consumption
    3. Fetching and Caching
    4. Network Type Detection and Handling
    5. Frameworks and Approaches
      1. Single Page
      2. No Page Structure
      3. 100% JavaScript Driven
      4. Mobile Debugging
  6. 4. The Desktop Web
    1. The Browser as a Platform
      1. Client Versus Server HTML Generation
    2. Device and Feature Detection
      1. Client-Side Feature Detection
      2. Client-Side userAgent Detection
      3. Server-Side userAgent Detection
    3. Compression
      1. GZIP Versus DEFLATE
      2. Minification
    4. JavaScript MVC Frameworks and the Server
      1. The Top Five Frameworks
      2. Backbone
      3. Ember
      4. Angular
      5. Batman
      6. Knockout
  7. 5. WebSockets
    1. Building the Stack
      1. On the Server, Behind the Scenes
    2. Programming Models
      1. Relaying Events from the Server to the Browser
      2. Binary Data Over WebSockets
      3. Managing Proxies
      4. Frameworks
  8. 6. Optimizing with Web Storage
    1. The Storage API
    2. The StorageEvent API
      1. What’s Racy and What’s Not?
    3. Using JSON to Encode and Decode
    4. Security and Private Browsing
      1. Security
      2. Private Browsing
    5. Who’s Using Web Storage?
      1. Using Web Storage Today
    6. Syncing Data from the Client Side
      1. Database Syncing with Backbone
    7. Using Web Storage in Any Browser
    8. Frameworks
      1. LawnChair
      2. persistence.js
  9. 7. Geolocation
    1. A Practical Use Case: User Tracking
    2. A Practical Use Case: Reverse Geocoding
    3. Frameworks
      1. geo-location-javascript
      2. Webshims lib
  10. 8. Device Orientation API
    1. A Practical Use Case: Scrolling with Device Movement
  11. 9. Web Workers
    1. A Practical Use Case: Pooling and Parallelizing Jobs
      1. Other Uses
  12. Index
  13. About the Author
  14. Colophon
  15. Copyright

Chapter 7. Geolocation

The Geolocation API provides scripted access to geographical location information associated with the hosting device. This gives your applications the ability to locate users and track their latitude and longitude as they move about. This functionality could be used for many interesting use cases such as:


Give your app the ability to schedule a task to alert users the moment they enter or leave a location. You could also target ads for users within a certain city or state.


Combine your app with a service like the Google Maps API (Figure 7-1), and you can translate latitude and longitude coordinates into actual postal addresses.

General tracking

Track distances driven, walked, or ran.

The API itself is device agnostic; it doesn’t care how the browser determines location. The underlying mechanism to obtain the user’s actual location may be through WiFi, GPS, or by the user actually entering a zip code into the device. The API is designed to gather both “one-shot” position requests and repeated position updates. Of course, Geolocation is no different than any of the other HTML5e APIs in regard to bugs, workarounds, and differences in implementations across browsers. After a review of the basics, we’ll dive into the cross-browser nuances.

Using the Google Maps API with Geolocation

Figure 7-1. Using the Google Maps API with Geolocation

To access a user’s location, run the following JavaScript: ...

The best content for your career. Discover unlimited learning on demand for around $1/day.