Documentation
checkspam
usage
boolean checkspam ( string post_variable )
parameters
post_variable : a variable returned by a form($_POST)
returns
A boolean telling you whether the variable contains mail headers or not.
The function verifies if no Mime-mail header (To: , Cc:) was put in the variable. This method is ofent used by spammers to use different servers to send unsocillited mails.
Be aware that no check is made on the content (Viagra, ...) of the text, this is not an intelligent (Bayes) anti-spam filter.
examples
if( checkspam($_POST['message']) )
die("Your message was considered spam");