Here are the most important sites that help you build a strong foundation of knowledge in the field of web programming and design:

1. Google and Youtube
We developed these two sites at the beginning because they are the basis for learning all fields in our time, as they help you find all the topics you want and arrange them for you according to your need and according to the importance of each result of your search, as these two sites connect you to the sources below and other sources that may appear in the future.
2. W3schools
This site, in turn, teaches you many programming languages ​​and starts with the trainee from the lowest levels in order to transfer you to higher levels of knowledge in the field you want to learn, as it is considered one of the most important sources of learning programming, especially programming websites.
3. MDN Web Docs
It is a Mozilla website. This website is similar to W3schools, but it has more branches and details.
4. CSS-Tricks
The idea of ​​this site was built on publishing matters related to the CSS programming language only, but it has branched out and expanded its sections and the areas that it explains after it gained high fame in the field of writing articles related to the field of programming and web design, and it is now one of the most important sites specialized in teaching programming languages ​​and solving problems facing programmers .
5. Google Web Development Blog
This site belongs to Google, as it contains a section dedicated to articles in the web field and another section for training, which helps you develop your skills and refine your information in the web field, with another section dedicated to the latest updates that have been made and you must know as a website programmer.
6. SitePoint
It is one of the educational sites that offers books and articles in many disciplines.
7. Stackoverflow
This site is not an educational site, but it is a site to answer all the questions asked by programmers (there are many other areas) where you will find a solution to all your problems in the field of programming. There are experts in a variety of fields.
8. Codepen
The idea of ​​this site is to share the work or code with other users. When you work on a project, you can publish it on the site and anyone can use or modify it as he wants. Where you will find a huge amount of ready-made projects and codes available for use and modification.
9. Github
This site is considered one of the most important sites for all programmers and developers, as a set of open source code is published for free for all to be used or developed.