how to filter??

[yuan]

all expert:
i done 1 guestbook, but how can i remove all the bad words and script when user key in??

[codeDV]

Using the strpos function:

<?php
$array_bad_words = Array ("bad word",
                          "offenceive words",
                          "php",
                          "naughty word");

$string = "This string contains bad words. The use of offenceive words is prohibitted in PHP this script.
Only naughty words can describe the inconvenience this causes.";

for ($x = 0; $x < sizeof($array_bad_words); $x++) {
  if (strpos (strtolower($string), $array_bad_words[$x]) !== false)
    echo ( "bad words found");
}
?>

This will pick up occurences of each word contained in the array. It might also be a good idea to load these words into an array from a database. This makes adding new words easier.

[xblue]

codeDV, I wonder why strpos?
wouldn't a simple stristr() be enough since you don't use the position?