Simple handy form validation functions used on a few diff forms.

form_validatin_functions.php

On Form Page:

$form_errors = process_form();

In the form (contains any validation errors) 

<?php validation_errors(); ?>


Form Elements (example)

<p>
<label>First Name *</label>
<input type="text" name="fname" <?php set_val('fname'); ?> />
<?php form_error('fname');?>
</p>


/////////------------------------

function process_form()
{
   if($_POST['username']==""):
        $error=true;
        $valdata['missing']['username']=true;
    else:
        if(username_exists($_POST['username'])):
            $error=true;
            $valdata['exists']['username']=true;
        endif;
    endif;

    if($_POST['email']==""):
        $error=true;
        $valdata['missing']['email']=true;
    else:
        if(!is_email($_POST['email'])):
            $error=true;
            $valdata['invalidemail']['email']=true;
        endif;
    endif;
// Etc 

    if(isset($error)):
        return $valdata;
    endif;

// Else continue processing form 

}

function validation_errors()
	{
		global $form_errors;
		if(isset($form_errors['error']))
			{
				foreach($form_errors['error'] as $error):
					echo '<p><span style="color:red">Error: '.$error[0].'</span></p>';
				endforeach;
			}
			
	}

function form_error($name)
	{
		global $form_errors;
		
		if(isset($form_errors['missing'][$name]))
			echo '<span style="color:red">This field is required</span> ';
			
		if(isset($form_errors['invalidemail'][$name]))
			echo '<span style="color:red">This is not a valid email address</span> ';
			
		if(isset($form_errors['match'][$name]))
			echo '<span style="color:red">This does not match</span> ';
			
		if(isset($form_errors['exists'][$name]))
			echo '<span style="color:red">This username already exists</span> ';

                if(isset($form_errors['roarcap'][$name]))
			echo '<span style="color:red">Sorry the captcha is incorrect. Try again </span> ';
 
	}
	
function set_val($key,$returnextra=true)
	{
		if(isset($_POST[$key]) && ($_POST[$key]!="")):
			if($returnextra):
				echo 'value="'.$_POST[$key].'"';
			else:
				echo $_POST[$key];
			endif;
		endif;
			
	}