getvpost question - pitch

Testing whether one can use 'variable' inside a php tag, and have the php work.

Both variables test OK, but each respectively comes with this message about the other when tested.

GET method:

this box's name is 'testvariable1'

POST method:

this box's name is 'testvariable2'

 

The problem message, due apparently to not writing in 'conditionals' code to weed out initial error: