HTML is used to define the content of web pages.
CSS is used to specify the layout of web pages.
PHP is a server scripting language, and a powerful tool for making dynamic and interactive Web pages.
SQL is a standard language for storing, manipulating and retrieving data in databases.
How to be Efficient in PhpStorm: An IDE that Really Matters
PHP Best Practices and Tips by Toptal Developers
Advanced Java Class Tutorial: A Guide to Class Reloading