checkbox and forms

[PAZII]

I have a form with one checkbox. How can I let the user on the next site only if he checked the checkbox?

[TruckStuff]

Two ways:
Check BEFORE form is submitted - Use javascript along the lines of:

if (document.forms.frm_blah.field_name.checked=='true')
   document.forms.frm_blah.submit();

OR

Check AFTER form is submitted - Put the following PHP on the ACTION page of the form at the top:

if (!isset ($_POST['field_name']))
   die ('Box not checked');

[dartcol]

This is what I generally use. It&s a beefed up version of Truckstuff's.

// if first name present trim and echo
	if ($_POST['fname'] != '')
		{
		$_POST['fname'] = trim($_POST['fname']);
		echo '<p>First Name: '.($_POST['fname']).'</p>';
		}

// if no first name display message saying field to be completed
// set $error var to TRUE
	else
		{
		echo '<font color=#ff0000>Please enter your first name.</font>';
		$error = 'TRUE';
		}

// check to see if $error is TRUE; if so provide a javascript BACK button for the user
	if (isset($error))
		{
		echo '<br><input type=button value=back onClick=history.back()><br>';