As a newbie to php and web development (I am a bit 'old school' coming from a desktop/Windows background) and I am working through Edition 5 of your excellent book and have hit an early snag....
I am running everything locally on my laptop using Wampserver 3.1.3 which I believe is configured correctly as it runs other code successfully and pushes it out to IE and Chrome without any problem. Chapter 1 contains the $_SERVER variable exercise which, on the face of it shouldn't pose any issues - but I am struggling to understand what is going on with my particular set up.
Basically, I am getting a null return from all the 3 server variable that you list in the exercise (the code initially failed with an invalid index error that I was able to resolve with the isset() function). When I do a phpinfo() check from within a php code snippet it suggests that these variables are not available (and all _SERVER variables are missing the leading $), whereas if I run phpinfo() directly from the link on the Wampserver homepage a much more comprehensive list of variables is displayed. Whilst this issue is clearly not a showstopper it highlights a fundamental learning issue that I need to understand if I am to code with confidence in php. Can you help please?