How can I use HTML5 in all browsers including IE7,8?

I want to use HTML5 because it supports in Iphone also and I really liked its capabilities but what can I do if it is not开发者_运维知识库 fully compatible with all browsers? Specially IE family. So is there a way by adding some js script e.t.c. so that HTML5 and its js api work normally in IE also as it works on other browsers like chrome, firefox and opera e.t.c.? So that I can use it without thinking of browser compatibility issues. There are also many game engines in html5 but what if this is not supported major IE browsers. Or can some one tell that how much advantage can I take of html5 without thinking of compatibility issues?

Thanks in advance

You can use http://html5boilerplate.com/ together with http://code.google.com/p/html5shiv/ and you're good to go.

For some other cool features, like video in old IE, you need to use workarounds like Flash for video and Javascript libs for canvas.

Simply put, if the markup is valid in HTML 4, change the Doctype and it will work as HTML 5.

If you want to use the new elements like <article> or <footer>, you will need to include a small javascript snippet in order to register those new types.

document.createElement("article");  
document.createElement("footer");  

This will make these new elements usable and stylable like an ordinary <div> element

Polyfills let you use new HTML5 apis on older browsers. The Modernizr project keeps a list of good ones: https://github.com/Modernizr/Modernizr/wiki/HTML5-Cross-Browser-Polyfills