Learning PHP

Ending lines
Each code line in PHP must end with a semicolon. The semicolon is a separator and is used to distinguish one set of instructions from another.

Comments
In PHP, we use // to make a single-line comment or /* and */ to make a large comment block.

Variables
When a variable is declared, it can be used over and over again in your script.

Rules for creating variables
A variable name must start with a letter or an underscore "_"

A variable name should not contain spaces. If a variable name is more than one word, it should be separated with an underscore ($my_string), or with capitalization ($myString)


Learning on W3Schools' PHP Tutorial