There's probably a simple solution to this, I simply don't know what it is.
I'm working on a php-driven web form, information to be submitted to a database. A number of the fields on the form correspond to not null areas in the db, so I need to figure out a way to prevent the end user from leaving those areas blank.
In the past, I've run into this problem in the Delphi programming environment. There, my solution was to create a pop-up dialog box warning the user that they had to fill in the required fields, and preventing the information from processing until they had done so.
I know I can refuse to process my data in the php file, since I'm drawing it from the form's data and validating it (currently against injection attacks, more as what I need becomes clearer) before doing anything else. But the form itself is supposed to run in the background; after finishing its work, the forms are supposed to redisplay, without any delay. Having to show the warning on the page would cause a few problems, and would also tend to make it look bad, as far as I can tell.
Is there some way I can create a 'pop-up' or equivalent warning box to let the end-user know that they've neglected to fill in a required field, like I'm used to in Delphi? Or is there some other, relatively simple, measure I could use to warn them about the fields? I'm not sure that simply marking the required fields will help; I've had trouble on both sides of that issue in the past. (Marked fields that wouldn't let me enter data, and fields that were required but not obviously so on a marked field form. And, of course, simple end-user [me] situational blindness.)
Any suggestions along these lines would be greatly appreciated.
Thanks in advance,