what is the second parameter in the following ereg function

[sean_paul]

function valid_email($address)
{
// check an email address is possibly valid
if (ereg("^{[a-zA-Z0-9_.-]+@[a-zA-Z0-9-]+.[a-zA-Z0-9-.]+$",} $address))
return true;
else
return false;
}

What does "$address" do?

Thanks

[suntra]

PHP.net :
ereg
(PHP 3, PHP 4 )

ereg -- Regular expression match
Description
int ereg ( string pattern, string string [, array regs])

It's simply the string you want to check. You check the address contained in.... $address...