JavaScript is free and runs on all modern computers and there are
numerous free tutorials explaining how to program in it. I have not read
through most of these, they just turned up near the top when I googled
"JavaScript tutorial" which usually means that a lot of people liked them
and linked them in their own web pages.
You might want to start by learning a little HTML. You don't need much, but knowing your way around a web page will help in placing JavaScript in it. You do not need to know about CSS unless you want to make very complicated web pages that do not display well on the browsers you did not test them on.
Note: This page is not being maintained, so some of the links
here may be/become broken. Sorry about that.
www.cs.brown.edu -- a single page without a lot of fluff, but not for beginners
www.echoecho.com -- many pages, with lots of detail (probably best if studied online)
www.webdevelopersnotes.com -- seems to assume some sophistication even among beginners
www.webmonkey.com -- seems to assume some HTML knowledge
www.tizag.com
see also their Beginner
and HTML tutorials
JavaScript Reference (not a tutorial) on www.Sun.com
www.w3schools.com
-- their pages are badly designed, and cannot be saved for offline review
www.pagetutor.com -- has obnoxious ads, but ads sometimes pay for better quality
www.davesite.com/webstation/html
Rev. 2017 April 22