forms - Include a $user.txt in php -

forms - Include a $user.txt in php -

i have little problem, dont know how solve.. i'm new kind of php stuff. how can include file, named $user + extension .txt ($user.txt), comes form:

<form action="status.php" method="post"> <input type="text" name="user" placeholder="user" /> <input type="submit" value="submit" onclick="submit" /> </form>

and, results (incluiding file) comes in same page.

do like

if(isset($_post['user'])) { include($_post['user'].".txt"); }

php forms variables include