Request to change this fetion php to input content and send short messages?

$data[ "user name"] = number;

$ data[" password "]= " password "；

$ data[" send to "]= number；

$data["message"] = "This is a test message!" ;

Revised as:

$ data[" username "]= $ _ REQUEST[' u ']；

$ data[" password "]= $ _ REQUEST[' p ']；

$ data[" send to "]= $ _ REQUEST[' s ']；

$ data[" message "]= $ _ REQUEST[' m ']；

Call mode:

xxxx.php？ U= number &; P= password &; S= number &; M= message content