the following code does not work when inserting text containing a hash symbol:
$query = mysqli_query($mysqli,"INSERT INTO users (username,password) VALUES ('".$username."','".$password."')");
the variables are escaped, but have not been manipulated otherwise. an example of what i'm inserting would be "hello#1". there is also no error being outputted via mysqli_error.
thank you.
ANSWER:
/facepalm
after some debugging; problem was actually related to the ajax request used to pass the strings.
turns out ajax can't pass a hash symbol directly and instead requires the use of encodeURIComponent().