May 8, 2007 – 8:45 am
Keeping the Web in Web 2.0
An HCI approach to designing web applications
Analysis of application state and its representation in browser historyand bookmarks.
One of the disadvantages of AJAX is that browser history and bookmarks of classic web applications are broken if not implemented specifically
Only some elements of interaction state are recorded in browser history.
Only some elements are recorded in bookmarks.
Only some state changes create history.
When one element changes, it may reset other elements to their default values (it’s said to dominate those).
The default value of one element may depend on the value of another.
External factors can change the application state
Types of Application States :
Hard State : Change creates history entry.
Soft State : Change is recorded in history, but doesn’t create new entry.
Transient State : Not recorded in history.
External state : Not recorded in history either, but recorded elsewhere.
Designing Application State :
In classic web applications, design decisions are built into the browser.
In Ajax web applications, they are explicit choices by the developer:
- Identify state elements.
- Assign them to application state classes.
- Decide their default values and dominance relationships.
- Decide how to implement them
Solution :
History: Store application state in browser history, and restore it on history navigation events.
Bookmarks: Store application state in a URL, and restore it when the URL is loaded into the browser.
See Example >>
Observe how certain application states are stored in the URL.
Posted in Web Technologies, User eXperience Design, AJAX, DOM, JavaScript, CSS, XML, XHTML, Code is Poetry |