8 HTML5 Features You Haven't Seen Before at lwsdeep
Posted on by Steve Workman About 3 min reading time
This month at London Web Standards, two in-depth HTML5 talks, covering bits which aren't in common usage at the moment, and what you can do with the bits that are. This is part one, Google's Michael Mahemoff (@mahemoff) on 8 HTML5 features you haven't seen before, and part two, Opera's Patrick Lauke (@patrick_h_lauke) on <video> and <audio>. Below are my notes and write-up. Enjoy!
This talk focused on 8 less-commonly used features of HTML5. Whether they're all actually part of HTML5 is up for debate, but they're all specifications being worked on for implementation in browsers, so that's enough.
Firstly, Michael had made his slides using HTML5, which worked really quite well, nice flashy transitions and all that and was a good example of some of the features he showed off (notably the history API) .
1. App Caching App caching is making web sites work offline: it tells browsers which files they should keep cached and re-load when the URL is requested. Whole apps can be cached like this and the iPhone and Android make good use of this. This is not the same as...
2. Client-side Storage Which is data storage accessed from JavaScript. You used to do this with cookies, but now you've got access to simple storage arrays, and WebSQL and IndexedDBs are coming. Both of these together replace services like Google Gears which was a stop-gap for this.
3. Cross Origin Resource Sharing One big problem with AJAX is that the XHR request can't request something on another domain. The work-around for this is JSONP which is a hack if there ever was one. CORS allows people to do this in an open way... which to me, is simply dangerous. However, it will have some uses, unlike...
4. Ping Which, apart from being a new social network, adds a bit of header information basically pinging a web site when a link is clicked. It's designed to replace redirects but I didn't really understand a good use case for it. If anyone wants to explain it, please drop me a line.
5. Web Sockets Web sockets allow for a connection to a server to be kept alive and events received, much like sockets created in any other programming language. Web sites like Facebook (for chat) and Swoopo currently use Comet for doing this and web sockets will allow them to get updates pushed to the page from the server without the ugly hacks.
6. History API I'm looking forward to this one: it allows for JavaScript inspection and manipulation of the browser's history stack (or array, whatever it is) without changing the URL to use the # technique. It's going to be very powerful for making applications where you don't change the page but lots of things change state and users use the back button a lot. I made a note that it's quite a bit like a view state, making an ASP.NET comparison, but that's a bit unfair.
7. Workers Web workers enables multi-threading in JavaScript. Finally! I hear you cry. It's not widely supported at the moment and it is about 25% slower than running the process in the main thread, but means you can do all sorts of things whilst the UI keeps updating.
8. Geo-location Used to be done by IP with big expensive databases, but can now be done with hooks into device hardware. Useful for a load of different applications, this will be one of the most widely-used of the HTML5 APIs.
And that's it. They're all under-the-hood improvements, and the browser makers are making it easier to do the cool stuff, which will bring in a lot of innovative web apps as people discover the power of these new tools.
Part two of #lwsdeep can be found here
Update: here's a picture of what's in HTML5 and what isn't by Bruce Lawson (Flickr)
