Open html-tags?

[Bob Day]

hi,

I have this function:
function clean_submit_data($data) {
$data = rtrim ($data);
$data = strip_tags ($data, "<br><i><u><b>"); //but don't strip: <br><i>...
$data = nl2br ($data);
return $data; //this will be stored into mySQL table!
}

What should I add to this funtion, so I know that $data won't contain open html-tags (<i><u><b>)?

My little sollution:
function clean_submit_data($data) {
$data = rtrim ($data);
$data = strip_tags ($data, "<br><i><u><b>");
$data = nl2br ($data);

$error = check_for_open_tags($data);
if ($error == 0) {
return $data;
} else {
return $error;
)
}

function check_for_open_tags($data) {
$error = 0;
????????? //do something to $data.
if(opentags) {
$error = 1;
}
return $error;
}

(Also does anyone have a good tut. about pattern matching?)