How to make changeable themes using CSS and JavaScript -

i'm pretty new css , javascript , wondering if make script allows change stylesheet site uses.

say: had green theme shades of green. user can change red press of button?

has idea how this?

you can set id link tag , switch css @ runtime.

html

<link type="text/css" rel="stylesheet" media="all" href="../green.css" id="theme_css" /> 

js

document.getelementbyid('buttonid').onclick = function () {      document.getelementbyid('theme_css').href = '../red.css'; };