Simple regex test fails

[Lassie]

I need to check that input is alpha numeric and use the following code which fails.

Is there a mistake in the eregi code?

if (eregi ('^[[:alnum:]]$', stripslashes(trim($_POST['address'])))) 
{
	$add = escape_data($_POST['address']);
} else {
  		$errors[] = 'You forgot to enter your address.';

}

[Lassie]

I realise that I also need to allow spaces in the address line so I have modified the expression but it still fails.

can anyone help please.

// Check for a address.
if (eregi ('^[[:alnum:]][[:space:]]{30}$', stripslashes(trim($_POST['address'])))) 
{
	$add = escape_data($_POST['address']);
} else {
  		$errors[] = 'You forgot to enter your address.';

}

[dsaba]

<?php
if (eregi ('[a-z0-9 ]+', stripslashes(trim($_POST['address']))))  {
	$add = escape_data($_POST['address']);
} else {
  		$errors[] = 'You forgot to enter your address.';

        }
?>

[Lassie]

Thank you.