Erase from 'strat" to "end'

[TKO]

Hello i am new to php and i need some help.
I'm looking to delete a section of a php file (start - end) from another file with a submit button.

So lets say i have logdata.php and index.php.
The submit button would be in the index.php and on the logdata.php i could have:

Start
test text
test text
test text
test text
End

Everything in between would be deleted while still leaving Start and End.
Any kind of help would be appreciated.
Thank you

[TKO]

lol strat... you know what i mean