single and double quotes work very differently in php, double quotes will still allow variables to be called inside them, but single quotes don't
there are some very common steps to debugging PHP code, first make sure your runnign the code on a server, as the PHP code won't run otherwise, check the version of PHP your using and the error message your
&_SERVER is an important part of PHP, &_SERVER is a PHP element that allows the program to access data about the server and how the user is accessing the server.
Normal: Morgan Sims Length: Uppercase: MORGAN SIMS Lowercase: morgan sims
Number formatting: 3,005, 1.2857