W3 school contain in depth information about web development . It has content from basic to advance level information.
It has html, CSI, phone, mysql, javascript, jquery. The information about this topics are short to the point and easy to understand. Then even provide certificate. If you want to create a best website I will recommend you to learn from this site. The topic which w3schools.com covered are css
Html
Javascript
Jquery
Php
Mysql
Bootstrap
Css
Xml
Angular js
Asp.net
Each topic covered are provided with example
So as to increase the understanding and this provide better quality of thinking , understanding and graping knowledge .
After covering it each topic there is also a test part in which we can we are able to know how much we are able to understand and through this we are able to test directly our knowledge
At last would suggest you that if you really wish to lean web development you must visit this site for once.