Java and Technology weblog
Intro to HTML5
Seth Ladd’s introduction was the highlight of the night for me.
aka Local Storage or DOM Storage
A way to store data on the client side (crash safe), making it crash safe and a good way to store, for example, user preferences. It is similar in some way to cookies, but offers more storage (5-10MB)and better programmatic interfaces.
Web SQL Database
Web Storage is useful for storing simple key value pairs but not for more complex relational data. That is where the new Web SQL Database API comes into play. It brings SQL to the client side. Databases can be created on the fly, updated queried like any server side database and can involve asynchronous transactions for a more responsive user experience.
Application Cache API
Prior to HTML, most browsers performed some kind of caching, but it could be inconsistent and of limited value (e.g. try refreshing a web page when you have no internet connection). With the offline application caching API, you (the developer) can specify exactly what should be cached by using a manifest file. This can result in a faster browser experience with less load on the server and, of course, means web pages can still be browsed even when you go offline.
Web workers are kind of like threads for your HTML apps. Your can now spawn background workers running scripts in parallel to the main page.
Bi directional, full duplex communication channels over a single TCP socket, designed to be implemented in web browsers and web servers.
How do we deliver a more desktop like experience to users?
Notifications can appear transiently in upper right hand corner. They fade in and fade out rather than being intrusive or modal.
Drag & drop
Imprecise forms of geolocation have been available for a while, for example via best-guess based on your IP address. But the new Geo Location capabilities provide more reliable ways to provide location specific or customized content and functionality.
New HTML5 Capabilities
Seth’s next section was HTML5 itself, i.e. the new capabilities in HTML itself.
New semantic tags
He talked about the new semantic tags (such as section/article/header and aside) that can be used as a way to avoid ‘div’itus.
New link relations
Several new rel attributes for the <a> and <ink> elements have been introduced for HTML5.
Is intended to provide a simple way to embed semantic markup into HTML documents, without the complexities of approaches such as RDFa (Resource Description Framework in Attributes).
Attributes for enhancing the accessibility of RIAs (Rich Internet Applications)
New form field types
e.g. can specify valid input ranges
Audio & Video
A Canvas is a 2Dimensional drawing surface that can be manipulated pixel by pixel.
New CSS Capabilities
HTML5 <video> and <canvas> Tags
The 2nd of the 3 presentations was by Tab Atkins Jr., on the new HTML5 <video> and <canvas> Tags.
It was started in 2005 and is made exclusively by developers working on their 20% projects.