Standards
- The World Wide Web Consortium (W3C)
- The Web Hypertext Application Technology Working Group (WHATWG)
- W3C’s Recommended Doctype Declarations
- Stanford University’s Copyright and Fair Use Website
HTML
- w3schools’ HTML Element Reference
- w3schools’ HTML Entities List
- W3C’s HTML Validator
- MDN’s article on “Dealing with files”
HTML5
- MDN’s article on “Using HTML sections and outlines”
- html5 Doctor’s HTML5 Element Flowchart
- w3schools’ HTML5 Semantic Element Reference
Cascading Style Sheets
- CSS Zen Garden
- w3schools’ CSS Properties Reference
- w3schools’ CSS Selectors Reference
- w3schools’ Colour Names Table
- Guy Routledge’s Interactive Box Model Demo
- W3C’s CSS Validator
- Estelle Weyl’s “CSS SpeciFISHity” table
- w3school’s article on “CSS Specificity” with respect to conflict
- MDN’s article on “Specificity” with respect to conflict
- “A Complete Guide to Flexbox” from CSS-Tricks
- Interneting is Hard’s Flexbox tutorial
Responsive Design
- “A pixel is not a pixel is not a pixel” article by Peter-Paul Koch of quirksmode
- “Using the viewport meta tag to control layout on mobile browsers” article from MDN
- “Making Sense of Device Resolution & Pixel Density” article by Alex Hernandez
- “Why Understanding Screen Size and Screen Resolution is Important” article by Ian Blair
- “Responsive Web Design” article by Ethan Marcotte
- W3C’s Media Queries Recommendation
- w3schools’ article on “Responsive Web Design – Media Queries”
- CSS-TRICKS’ article on “Media Queries for Standard Devices”
- W3C’s Mobile Web Best Practices
- Smashing Magazine articles:
- “Using Media Queries For Responsive Design In 2018” by Rachel Andrew
- “Media Queries Are Not The Answer: Element Query Polyfill” by Tyson Matanich
- “Element Queries, And How You Can Use Them Today” by Tommy Hodgins
JavaScript
- w3schools’ JavaScript and HTML DOM Reference
- Ralf S. Engelschall’s ECMAScript 6 New Features: Overview & Comparison
- ECMAScript 6 Compatibility Table by kangax, webbedspace & zloirock
- Ilya Kantor’s tutorial on “JavaScript Event Capturing and Bubbling”
- MDN’s article on JavaScript’s “Arrow function expressions”
jQuery
PHP
- PHP Documentation
- The PHP Framework Interop Group’s Standards Recommendations
- PHP’s documentation on Operator Precedence
Browsers
- statcounter’s Browser Market Share
- MSDN’s article on “Defining Document Compatibility in IE”