javascript.info
The Modern JavaScript Tutorial
From variables to async, with tasks after each chapter. Still the site people send juniors to.
JavaScript
Catalog / Web
Web
24 primers · 15 per page.
web.dev
web.dev learn
CSS, performance, and forms written as short lessons instead of a dump of specs.
HTMLCSSJavaScript
phptherightway
PHP: The Right Way
A map of current PHP practice: Composer, PDO, dates, and what to stop copying from 2009 blogs.
PHP
css-tricks
owasp
OWASP Web Security Testing
Not a friendly intro. Use it when you already ship forms and care who fills them.
PHPJavaScript
internetingishard
Interneting Is Hard
HTML and CSS from a blank file. Slow, illustrated, still good for the first week.
HTMLCSS