what is the difference between bootstrap.min.css and bootstrap.min.js ? Why bootstrap.min.js need to be included?
<link rel="stylesheet" href="http://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/css/bootstrap.min.css">
and
<script src="http://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/js/bootstrap.min.js"></script>
They're both minified versions of the complete Bootstrap style (CSS) and components (JS). You don't need to include the JS to use the Bootstrap styles (responsive grid, buttons, tables, typography, panels, etc..).
However, you do need to include the JS if you want to use the Bootstrap JavaScript components (modal, carousel, data-attributes, scrollspy, tooltop, etc..).
Bootstrap.min.css contains the CSS necessary for the Bootstrap to work correctly.
Some of the functionality offered by the bootstrap aren't possible though using only plain .css and this is where javascript comes into play.
Bootstrap.min.js contains javascript code necessary for running Bootstrap.
.css is a stylesheet file and .js is javascript file
all javascript components of bootstrap are bundled into bootstrap.min.js
Well min.css obviously minifies the style for core bootstrap CSS while min.js minifies javascript modules. I think you should google some basic web tutorials before you start working with bootstrap.
You can need their own functions, check this: http://getbootstrap.com/javascript/
