PHP generated verification code does not show

PHP generated verification code does not show
PHP uses a class library of its own writing

It can be displayed separately in a file, but after a route jump, it's not coming.

What's going on here?

------Solution--------------------
You still don't have a number to figure out the relationship of these two URLs
If the test3.php is executed through the following connection, then you first have to consider the program you practice more output what?
such as BOM headers, spaces, blank lines, and other things that are not in the picture data

