Highly recommended for beginners who have just started their web development
journey.
W3Schools
Complete Web Development Tutorials
W3Schools is a web developers site, with tutorials and references on web
development languages such as HTML, CSS, JavaScript, PHP, SQL, W3.CSS, and
Bootstrap, covering most aspects of web programming.
Interactive Coding Tutorials
W3Schools
Complete Web Development Tutorials
Test it yourself is a best option to practice as soon as you learn.
Codecademy
Learn to code
An Interactive mission based challenges to learn code simpler and fast.
Integrated Development Environment on web
CodePen
Front-end Web Development Playground & Code Editor
a social development environment for front-end designers and developers. It's
the best place to build and deploy a website, show off your work, build test
cases, and find inspiration.
JSFiddle
Online IDE for HTML, CSS, and JS
an online community for testing and showcasing user-created and
collaborational HTML, CSS and JavaScript code snippets, known as 'fiddles'.
Visual Reference Guides
HTML Reference
Learn by Example
a free guide to HTML. It features all elements and attributes.
CSS Reference
Learn by Example
a free visual guide to CSS. It features the most popular properties, and
explains them with illustrated and animated examples.
Front-end Frameworks
Bootstrap
World's most popular Front-end component library
an open source toolkit for developing with HTML, CSS, and JS.
Foundation
Responsive Front-end Framework for Websites & Emails
a family of responsive front-end frameworks that make it easy to design
beautiful responsive websites, apps and emails that look amazing on any device.
UIkit
Modern UI Framework for Modern Web
A lightweight and modular front-end framework for developing fast and
powerful web interfaces.
SemanticUI
UX Oriented Development Framework
Semantic empowers designers and developers by creating a shared vocabulary
for UI
Ultimate Guide For Web Development
Become a Full Stack Web Developer
Highly Recommended Guide which is constantly updated.
100+ Free resources for learning Full Stack Web Development.