Possible Duplicate:
Validate Email in php
how to validate email IF user did fill up form field ( do not validate if field is not modified ) ?
Example:
if ($formemail ="" ) /* user DIDN'T enter email/not filled up email field */
{
/* do not validate and do not =mail($,$,$,$) */
}
but if field is modified THEN validate if its ok then =mail($,$,$,$)