If statements checking for form completion?
I'm writing code for a conference registration page, and having a friend write the php for it. I've never worked with html forms before by the way.
How can I create an if statement that dosn't allow a viewer to submit their form if they have not filled out all the forms and also checked a confirmation text box? IE, an error box or page comes up if they have left a blank field and not clicked the text box. Hopefully I'm clear in what I'm talking about.