+ 6
Hi. I really like edX! Search it on Google. I like it cauz courses r 'free'. U only need to pay for certificate if u want it. Edx gave me great introduction to Python. This particular course was offered by Microsoft. I've seen HTML5 & CSS but haven't explored it. Good luck!
+ 5
w3schools.com
+ 5
w3schools is fine, I also like (for HTML and CSS):
http://www.tizag.com/htmlT/
http://www.tizag.com/cssT/
+ 4
https://developer.mozilla.org/en-US/docs/Web/HTML
+ 3
Code Academy
+ 3
FCC (Free Code Camp) is one if the best site for progressive learning.
+ 2
You can search google for it,Google helps a lot,One search can get you thousands of results within moments.Just search something like "HTML tags,Elements,Attributes,Structure"
Or just type in,HTML Learning Online
+ 2
w3schools
+ 1
W3schools is good