1) If I\'m already using Modernizr, will I then even need HTML5 Shiv to enable HTML5 tag support for IE?
2) Is HTML5 Shiv only for IE, or for all browser who don\'t have
1) If I'm already using Modernizer then even will I need HTML5 Shiv to enable HTML5 tag supports for IE.
You don't need to separately include html5shiv, because Modernizr includes it:
As of Modernizr 1.5, this script is identical to what is used in the popular html5shim/html5shiv library.
http://www.modernizr.com/docs/#html5inie
2) and is HTML5 Shiv only for IE or for all browser who don't have native HTML 5 support. like older version of Firefox, Safari, Chrome etc.
It's only for Internet Explorer.
Older versions of other browsers don't need it: http://caniuse.com/html5semantic
And the recommended snippet to include it is:
<!--[if lt IE 9]>
<script src="//html5shim.googlecode.com/svn/trunk/html5.js"></script>
<![endif]-->
Which will only ever run for IE less than 9.