Lessons 5 and 6

Lesson 5 was pretty straightforward. My only question/confusion is what the necessity of global keywords is. From the example in the lesson it looks like the keywords are just there to say "these are constants and not variables." They aren't being defined, just listed. Do the keywords just serve as indicators that those variables are actually constants and not variables limited to the context of that function? Can keywords be used outside of functions?

I appreciated the Lesson 6 Form video tutorial. Very nice and very helpful. Definitely digging all of the resources in this class. While the amount of information can be overwhelming, I don't feel lost and there are a lot of options for getting answers.

My only question on Lesson 6 is regarding the last sentence of the POST vs. GET section. Confusion in green text:
"The method attribute identifies one of two ways the data can be sent along with the web page, either via "POST", or "GET" Neither of these is not part of PHP, but of the HTTP Protocol."
I think I am just confused by the double negative (neither/not). I assume what is being said here is that POST and GET are not part of PHP, rather, they are HTTP.

Could use a little more info on unset(), which was used in the two form examples at the end of Lesson 6, but maybe it is covered in Lesson 7.

Started reading around 10am this morning. Spent some time with the links, videos and examples. Started the homework in class on Monday. Spent about 30 minutes on it. Just a little further to go.