PHP is a Hypertext Preprocessor. This essentially means that PHP dynamically writes web pages for you. So it can query a database and print a report from it, or change CSS and such based on specific criteria.
Cookies allow you to set variables that are persistent between multiple visits to a website.
You can validate that variable values look how they are supposed to by using filter_var in PHP. Filter_var determines if an email address, IP address, Int, Float, etc are formatted how they are supposed to […]