empty elements: https://repl.it/GNrQ/2
nesting: https://repl.it/GOEW
headings: https://repl.it/Ft5E/6
paragraphs: https://repl.it/Ft77/3
div: https://repl.it/GOGZ
span: https://repl.it/GOFU
divs and spans: https://repl.it/FvbQ/3
HTML attributes: https://repl.it/GEuu/1
Class: https://repl.it/GJTb/1
Boolean attributes: https://repl.it/GOMl/1
Links: https://repl.it/GSnM
Href: https://repl.it/GKqf/5
Target: https://repl.it/GKoj/2
<ol>: https://repl.it/Fvha/12
<ul>: https://repl.it/GEv1/1
<dl>: https://repl.it/GExe/1
nested lists: https://repl.it/GIkf/2
<img>: https://repl.it/GOWg
<table>: https://repl.it/GDxG/0
<input>: https://repl.it/GQQH/3
checkbox: https://repl.it/GAw6/0
radio button: https://repl.it/GAtY/2
<textarea>: https://repl.it/GAx8/0
Validation: https://repl.it/GFgo/1