Chroder.com

Now on to the good bits! The validation script:
[code lang="php"]

function getInvalid($array)
{
$invalid = array();

foreach($array AS $k => $v)
{
$v = urldecode($v);

$okay = true;
switch($k)
{
case ‘username’:
if(!preg_match(’#[a-zA-Z0-9-_]{3,10}#’, $v))
$okay = false;
break;

case ‘email’:
if(!preg_match(’#^([a-zA-Z0-9_-.]+)@([a-zA-Z0-9_-.]+).([a-zA-Z]{2,5})$#’, $v))
$okay = false;
break;

case ‘password’:
if(strlen($v) < 3)
$okay = false;
break;

case 'comments':
if(strlen($v) > 255)
$okay = false;
break;

default:
unset($okay);
break;
}

if(isset($okay))
$invalid[$k] = $okay;
}

return $invalid;
}

function writeJS($item, $okay)
{
echo “error_$item = getItemMain(’error_$item’);n”;
echo “if(error_$item) {n”;

if(!$okay)
echo “error_$item.style.display = ”;n”;
else
echo “error_$item.style.display = ‘none’;n”;

echo “}nn”;

}

?>[/code]
(Note, I have a hidden form element ‘do’ in the HTML that holds no particular value, but in the PHP script it checks to make sure it exists before continuing. I did this to make sure the script didn’t function the the frame was first loaded. You could always just make the source of the frame empty, or check for the submit button instead. But I’m too lazy to change it :-P).

We have an array, $invalid, that holds the status of all the form fields. If a field is correct, then the $invalid array index for that field holds true, and if it is invalid, it holds false.

The next bit of Javascript code is just a method to get object from the ‘main’ frame by using it’s ID. It’s a modified version of my ‘getItem’ function I use a lot.

After that, we get PHP to loop through all the items in $invalid and then call a PHP function writeJS() to write the proper JS for it. If the item is false (or the field is invalid), then the JS outputted makes the error div on the main frame visible. If it’s true, then the JS makes the error div hidden. Simple as that!

Then finally after all that, we get PHP to check if there were any invalid form fields (using in_array(), checking for false within $invalid). If there isn’t, then we output some JS to change the action and target to the “real” form handler, then we fire up the submit() event to submit the form.

Hopefully I explained that well enough! As promised, here is the working example: clickety.

This entry was posted on Saturday, October 2nd, 2004 at 12:37 pm and is filed under Dev. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.