how to force entry into input boxes

[brambleon]

This is a real newbie question, and I am thinking probably is more HTML than PHP, but I thought I'd ask anyway. I've created a site that requires the user to enter information into input boxes. I want them to have to fill these in before going on to the next page (where a PHP error will be displayed if they are not filled in). How do I check to make sure the user has entered information into them? Thanks for any help.

[LordShryku]

Here's what I use. It's sort of a double check.

Say you have a input named text1. On the next page....

if(!isset($_POST['text1']) || empty($_POST['text1'])) {
   die("You must fill in text1");
}

It checks if the field is set and not empty. If either condition exists, it stops the script with that error.