iPXE and calling PHP

[ndog]

Thanks for your help
I am a novice and mostly learnt by experimentation than theory.
initrd is different that it does not process any ipxe commands while chain will process ipxe commands, hence won't crash as far as I can tell.
Regarding the php, an example would help, like the example on the params page. chain http://boot.ipxe.org/demo/boot.php##params
What is a specific php documentation term I google for?