That's a vague question, sounds almost like what is life. So let's see ... website is code, can be plain old html but can also be php, asp.net, ruby on rails, etc. But life is also about beauty, and beauty is design and layout all wrapped up in CSS. So CSS, learn it and what ever code tickles your fancy, learn it, or take a short cut (and chicken out on life ) and use a cms template like joomla, wordpress, blogger, etc.
Finally, google makes life easy. Almost anything you need to learn about web dev is on the internet so learn how to use google and just google it!