PHP is a server-side, open-source, HTML-embedded scripting language used to drive many of the world's most popular web sites. All major web servers support PHP enabling normal HMTL pages to embed code fragments that get interpreted before being served up to requesting users.
PHP is a modern language for web site development. It supports both procedural and object-oriented programming plus integrated database support. It often serves as the glue code to connect web pages to a server-side database like MySQL. An interactive web site is event driven. Each user click, menu selection or keyboard action can initiate a thread of execution that runs many lines of code.
Use MacA&D or WinA&D to diagram the structure of a PHP program. The developer can show team members how the program works and where changes are needed. Incrementally draw new classes, then click to generate code that exactly implements the design.
MacTranslator or WinTranslator scans PHP code to extract design information to a text file. Import that file into MacA&D to generate UML class diagrams or Structure Charts for each thread of execution.