You are previewing JavaScript Web Applications.

JavaScript Web Applications

Cover of JavaScript Web Applications by Alex MacCaw Published by O'Reilly Media, Inc.
  1. JavaScript Web Applications
    1. SPECIAL OFFER: Upgrade this ebook with O’Reilly
    2. Preface
      1. Who Is This Book For?
      2. How This Book Is Organized
      3. Conventions Used in This Book
      4. Accompanying Files
      5. Code Conventions
      6. Holla
      7. Author’s Note
      8. Safari® Books Online
      9. How to Contact Us
    3. 1. MVC and Classes
      1. Early Days
      2. Adding Structure
      3. What Is MVC?
      4. Toward Modularity, Creating Classes
      5. Adding Functions to Classes
      6. Adding Methods to Our Class Library
      7. Class Inheritance Using Prototype
      8. Adding Inheritance to Our Class Library
      9. Function Invocation
      10. Controlling Scope in Our Class Library
      11. Adding Private Functions
      12. Class Libraries
    4. 2. Events and Observing
      1. Listening to Events
      2. Event Ordering
      3. Canceling Events
      4. The Event Object
      5. Event Libraries
      6. Context Change
      7. Delegating Events
      8. Custom Events
      9. Custom Events and jQuery Plug-Ins
      10. Non-DOM Events
    5. 3. Models and Data
      1. MVC and Namespacing
      2. Building an ORM
      3. Adding ID Support
      4. Addressing References
      5. Loading in Data
      6. Populating Our ORM
      7. Storing Data Locally
      8. Adding Local Storage to Our ORM
      9. Submitting New Records to the Server
    6. 4. Controllers and State
      1. Module Pattern
      2. Adding a Bit of Context
      3. State Machines
      4. Routing
    7. 5. Views and Templating
      1. Dynamically Rendering Views
      2. Templates
      3. Binding
    8. 6. Dependency Management
      1. CommonJS
      2. Module Loaders
      3. Wrapping Up Modules
      4. Module Alternatives
      5. FUBCs
    9. 7. Working with Files
      1. Browser Support
      2. Getting Information About Files
      3. File Inputs
      4. Drag and Drop
      5. Copy and Paste
      6. Reading Files
      7. Custom Browse Buttons
      8. Uploading Files
      9. jQuery Drag and Drop Uploader
    10. 8. The Real-Time Web
      1. Real Time’s History
      2. WebSockets
      3. Real-Time Architecture
      4. Perceived Speed
    11. 9. Testing and Debugging
      1. Unit Testing
      2. Drivers
      3. Headless Testing
      4. Distributed Testing
      5. Providing Support
      6. Inspectors
      7. The Console
      8. Using the Debugger
      9. Analyzing Network Requests
      10. Profile and Timing
    12. 10. Deploying
      1. Performance
      2. Caching
      3. Minification
      4. Gzip Compression
      5. Using a CDN
      6. Auditors
      7. Resources
    13. 11. The Spine Library
      1. Setup
      2. Classes
      3. Events
      4. Models
      5. Controllers
      6. Building a Contacts Manager
    14. 12. The Backbone Library
      1. Models
      2. Collections
      3. Views
      4. Controllers
      5. Syncing with the Server
      6. Building a To-Do List
    15. 13. The JavascriptMVC Library
      1. Setup
      2. Classes
      3. Model
      4. Using Client-Side Templates in the View
      5. $.Controller: The jQuery Plug-in Factory
      6. Putting It All Together: An Abstract CRUD List
    16. A. jQuery Primer
      1. DOM Traversal
      2. DOM Manipulation
      3. Events
      4. Ajax
      5. Being a Good Citizen
      6. Extensions
      7. Creating a Growl jQuery Plug-in
    17. B. CSS Extensions
      1. Variables
      2. Mixins
      3. Nested Rules
      4. Including Other Stylesheets
      5. Colors
      6. How Do I Use Less?
    18. C. CSS3 Reference
      1. Prefixes
      2. Colors
      3. Rounded Corners
      4. Drop Shadows
      5. Text Shadow
      6. Gradients
      7. Multiple Backgrounds
      8. Selectors
      9. Transitions
      10. Border Images
      11. Box Sizing
      12. Transformations
      13. Flexible Box Model
      14. Fonts
      15. Graceful Degradation
      16. Creating a Layout
    19. Index
    20. About the Author
    21. Colophon
    22. SPECIAL OFFER: Upgrade this ebook with O’Reilly
O'Reilly logo

WebSockets

WebSockets are part of the HTML5 specification, providing bidirectional, full-duplex sockets over TCP. This means that servers can push data to clients without developers resorting to long polling or browser plug-ins, which is quite an improvement. Although a number of browsers have implemented support, the protocol is still in flux due to security issues. However, that shouldn’t put you off; the teething problems will soon get ironed out and the spec will be finalized. In the meantime, browsers that don’t support WebSockets can fall back to legacy methods like Comet or polling.

WebSockets have significant advantages over previous server push transports because they are full-duplex, aren’t over HTTP, and persist once opened. The real drawback to Comet was the overhead of HTTP—every request also had a full set of HTTP headers. Then there was the overhead of multiple extraneous TCP handshakes, which was significant at high levels of requests.

With WebSockets, once a handshake is completed between client and server, messages can be sent back and forth without the overhead of HTTP headers. This greatly reduces bandwidth usage, thus improving performance. Since there is an open connection, servers can reliably push updates to clients as soon as new data becomes available (no polling is required). In addition, the connection is duplex, so clients can also send messages back to the server, again without the overhead of HTTP.

This is what Google’s Ian Hickson, the HTML5 specification ...

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