I am writting a user logon page, and want to add an error check to it so that if the username or password field are left blank an error message is printed to the screen. I have been trying the following ways of doing this 
   if($username eq null) {

                display_error_message();
       }

[download]
This is bringing back an internal software error. Can anybody see why this is happening? Thanks

In reply to creating an error message by Anonymous Monk

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