Web Coding in PHP
PHP code is embedded directly into the HTML using special script tags. The mod_php Apache module allows Apache to interpret PHP files. Any text not found inside the script tags (e.g. raw HTML) is not interpreted at all, but directed to the output.
This makes PHP much easier to use than other langauges, which may require that all raw text be printed using a print() statement of some kind.
I used the newer mysqli library instead of the older mysql library, which now generate warnings.