HTML 5, what should I tell my clients?_问答_开发者

More of my clients lately are asking me about开发者_如何学运维 HTML 5 and I'm trying to get a sense of what to tell them. How long until all the major browsers have standard support for it? How long until I leave HTML 4 behind and only code new projects in HTML 5? What are you telling your clients?

Are they asking about specific HTML5 features or HTML5 in general? At my company we haven't said anything to the clients, but we do set the HTML5 doctype as well as using some HTML5 markup - but only markup that works in non-HTML5 compliant browsers. HTML5 doesn't necessary mean you discard older browsers, it depends on which features you implement. You can still use audio and video tags, as long as you keep a flash fallback - as an example. HTML5 form tags are poorly implemented even in bleeding edge browsers, so using them are not an option.

I suggest you read Dive Into HTML5 to see how you can work with HTML5 today, but still support non-HTML5 browsers.

I'll throw in another link; Modernizr is a JavaScript library that come in handy if you want use bleeding edge HTML5 or CSS3 features, it detects support for HTML5 tags and some (all?) CSS3 properties.

You've already gotten some good answers, but I'll chime in as well. I wouldn't give your client a blanket "yes" or "no" on html5. I'd take a look at what all has changed and then break it down into sections based on how well it's supported.

The Doctype:

Nothing is stopping you from switching to the html5 DOCTYPE today. Even browsers that don't understand html5's new tags (most notably IE 6-8) will recognize <!DOCTYPE html> as a valid doctype and not switch into quirks mode. After declaring that your document is an html5 document, you're free to use (or not use) html5's new tags to your heart's content. Personally, I've started using the html5 doctype on websites -- even if I have no immediate plans to use html5's new features -- because there isn't any negative side effect, and as a bonus I don't have to try to remember the correct way to write a doctype and charset everytime I start a new page (which I have to do with html4/xhtml).

New (Layout) Tags:

Next, you have to figure out why your client is interested in using html5 in the first place. My guess is that they're interested because it sounds trendy and cutting edge. In reality, one of the biggest benefits of many new tags (such as <section>, <nav>, <footer>, <aside>, etc) is that they make your code much more readable than it would be if the page was filled with <div>s everywhere. This is a great advantage for the coder (and in the future it might help with accessibility), but right now, this change probably makes very little difference to the client.

New Features (Video and Audio):

Alternative, the client might have specific html5 features that they want their site to use. Two of the most popular are the <video> and <audio> tags. The great thing about these is that you can easily fallback to Flash, so you don't have anything to lose (as far as browser support goes) by using them.

Complex Features:

Other popular new features are <canvas>, geolocation, and local storage (not exactly html5, but related). For these, the fallbacks (if they exist) require a lot more work on your part. If your client really wants these features, you'll need to figure out which browsers they (or their customers and site visitors) are using, and what percent of their target audience they're willing to leave behind.

Conclusion

That got a little long-winded; long story short, I'd tell your client this: "I'll gladly start using some html5 features immediately. Remember, though, that the specification is not finalized, and it will continue to change over the next 10 years. Around 50-60% of our clients may be using browsers that don't support some of html5's new features, so we'll need to do thorough analysis before adding certain complex features of html5."

If the clients are OK with using the browsers that support HTML 5 for their applications, then why not :)

If they don't want to use the browsers (and versions) that doesn't support HTML 5, then they can't have it, thats what I would say.

Edit:

OK let me put it this way. If they are asking for a suggestion, then ask them what browsers and versions are they comfortable with, if they fall into the area where HTML 5 is supported, then tell them that they can move to HTML 5, adding that its in a nascent state, but support is growing at a good pace.

How long until all the major browsers have standard support for it?

Never. If you look at HTML5 as a whole (which you shouldn't), no broser will ever support it. For each browser, there will always be dozens of features defined in HTML5 which the given browser does not implement.

How long until I leave HTML 4 behind and only code new projects in HTML 5?

The language hasn't changed. It's still HTML. So, you cannot say "I code in HTML 4" or "I code in HTML5". You code in HTML.

HTML5 introduces new features. For each feature, you decide independently if you want to use it in your projects. There is stuff defined in HTML5 that you can use today. On the other side, there is stuff defined in HMTL5 that currently isn't implemented in any browser. The point is, it depends on the given feature.

Another key question is: What browser(s) do the majority of your clients use? Since medium to large size companies tend to be very resistant to changing browsers, what they use now is what they're likely to use for the forseeable future.

For clients using mostly Firefox, the answer is that Firefox supports a good deal of HTML5 now (version 3.6), & even more in version 4 (2011). For clients using mostly IE, they'll have to wait until version 9 (2011).