header("Location:blah...") - passing variables

Hi, I wonder if someone could tell me whether or not the following is possible? I have an HTML form which passes a username and password to a PHP script for validation. If either is not valid, I would like it to return to the previous page - carrying with it a variable plus the submitted form information... =-=-=-=-=-=-=-=-= if (strlen ($password1) <4 ) { $err = "Password must be more than 4 characters long"; header("Location:http://somelocation.php"); // ^-- at the location, the $err and form variables will be available exit; } =-=-=-=-=-=-=-=-= Is it possible to this without using an HTML form? Thanks very much in advance. - Best regards, Lee