How to Provide support for the browsers who don't support HTML 5?

I want to create a webPage using HTML 5 which will use all the attractive features of HTML5 i.e. audio, video, autofocus, placeholder, required, email, url, number etc. and the webPage should also have support for the browsers which dont support HTML5 like IE or some versions of other popular b开发者_JAVA技巧rowsers such as Chrome, Firefox, opera etc.

How do I start working on that, as You might guess that this is just for the experimental purpose and I am supposed to it asap... so please suggest me any help, site or blog or tutorial or example.. I have seen hhtml5Doctor.com and diveintohtml5.ep.io ... the sites are of great help...

Use progressive enhancement. The diveintohtml5 already tells you how: http://diveintohtml5.ep.io/detect.html

html5boilerplate is a good start, it includes modernizr/html5shiv for barebones support of the new elements.

Other things may need javascript/flash fallbacks.

You can make use of the fact that browsers will ignore tag that they don't understand. So, for example, you can have an audio tag and inside that put an object tag for a flash audio player. The HTML5 browser will understand the audio tag and do the right thing, and ignore the child content. An older browser will see the audio tag and throw it away beacuse it doesn't understand it, but will render the child contents of the tag instead (the flash player).

swfobject and Modernizer are really nice tools... u must give them a try... I would personally recommend swfObject due to very good support.