Over to the Pavilion for Jeremy Keiths Ajax session...
- Short version - Is Ajax a Flash Killer - NO!
- Long version...
- Ajax was coined by Jesse James Garret to describe existing technologies
- Buzzword
- Sounds cool
- Myth based
- Has the letter x in it
- Gets associated with web 2.0 along with rss etc (Note: he refused to say "web 2.0" - only inferred it)
- What is it?
- XML is not necessarily intrinsic to it
- Javascript is integral
- Asynchronous is the key
- Server sends bits to you as you're interacting with the page on browser
- Result is an apparent increase in speed
If traditional web was letter writing, Ajax is instance messaging
- Didn't catch who he was quoting here.- His def:
Ajax is a way of communicating with the server without refreshing the page
- XMLHttpRequest - not snappy enough for buzzword
- Been around since IE5
- Invented by Microsoft
- Mozilla, Opera and Safari eventually took it on
- W3C is turning it into a standard
- Samples
- Amazon.com (rating stars)
- Newshutch.com (Rss)
- Meebo.com (Instant messaging - overkill!)
- Googlemaps
- Ajax is useful at the left of the slider, less useful at the right
- Flash is opposite
- Principle of Progressive enhancements
- Positive spin on degrading gracefully
- Workflow
- 1. Start with content which is semantically structured (HTML)
- 2. Add presentation layer (CSS)
- 3. Add behaviour (AJAX)
- Take away any layer and it still degrades down to the last layer and works/content is viewable
- New term - Hijax
- Termed by Jeremy Keith
- Workflow
- Build your application old-fashioned way
- Get completely working with conventional calls
- Then use JavaScript to hijack calls and replace with XMLHttpRequest
- So when something goes wrong - app still works
- Not many people doing it this way
- If you can't apply progressive enhancement then you've crossed the line - Ajax is no good - use Flash
- Pattern recognition
- Do small stuff with Ajax
- Logon feedback
- Add to cart
- Rate this
- Add a comment
- Do small stuff with Ajax
- The alternative to progressive enhancement is the Plugin
- If you're going to cross a technological boundary (i.e. user must have JavaScript) then go for a boundary which is a rich experience (Flash)
- When?
- Widgets (i.e. sliders)
- Audio/video
- Image manipulation
- Choose best tool for the job - ask: "Why am I doing this?"
- Design challenges
- Not letting technology get out of control
- Keeping the user at the core
- This is something Flash devs have been doing for years
- Beyond the Browser
- Ajax screws back button and bookmark
- Something that Flash has had to deal with for years
- If bookmark of back button doesn't work and needs to, then you're changing too much of the page!!!
- User feedback for clicks - need to tell user what is happening (i.e. load bar)
- What happened feedback for user
- Let people know what changed
- Conventions
- Yellow fade (37Signal.com)
- Visual effects
- What is good design?
- "Being able to justify every pixel" lookup author
- Why does it do that?
- User testing!!
- Accessibility - Ajax has really bad accessibility
- Ajax can't pick up if a screenreader (SR) is present
- Myth that SRs don't do JavaScript
- They do part of JavaScript
- So instead of locking out all JavaScript func and dropping down to presentation layer - it tries to do it and screws up
- Answer? Flash + Ajax
- Use a Flash movie (1px) to detect if a screenreader is present and then tell the Ajax via a JavaScript method
- Analogy was Flash Gordon movie: together Flash and Ajax (Gordon's spaceship) combined to kill Ming the Merciless ;)
- His DOM Scripting book looks really good
- Numbers for Ajax enabled browsers is hard as different factors
- JavaScript enabled
- XMLHttpRequest in IE5/6 is activeX control so activeX needs to be enabled
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