Server validation on an update page
I am trying to add a server validation to an update page where users are allow to enter their sales ID. Example, if a user does not already entered his/her sales ID, the user can update their profile and enter a unique sales ID. An error message will display if user is trying to enter a sales ID that is already entered. Second scenario will be if a user has already entered his/her sales ID but would like to update something else. Is there a way to prevent the server validation from activating? When I try to update other than the sales ID, I get the following
Warning: Cannot modify header information - headers already sent by (output started at E:\vhosts\dev-3\plugins\login\Untitled-5.php:6) in E:\vhosts\dev-3\webassist\form_validations\wavt_scripts_php.php on line 85