$_GET['F'] in line 6 is not defined? May I ask what it means?

Question

$_GET['F'] in line 6 is not defined? May I ask what it means?

Answer 1

Assume that your url is http://www.test.com/test.php?f=test, then f is the parameter name, test is the value of f, and the parameters submitted by get are all in the address bar. , post submission, there is no post submission parameter in the url address bar, "$_GET['F'] is not defined" It should be because the address bar does not have the f parameter, and it cannot get the value

Answer 2

It’s not that there is no f in the get request,

Answer 3

Is 'F' the value of the input name attribute?