check for duplicate value in input

I have code that checks mysql for duplicate entries in a database and issues error through ajax. That works fine. My problem is that I have no way for checking duplicate entries in the form when the form is sent to php for processing. The inputs are created by a jquery change on a slider so there could many inputs created by the user from which they create unique codes. What I am trying to do is check that if a user enters the same number in the form then issue an error. Am I better doing this before it reaches php using jquery?  I hope someone can help with this. Thanks

$duplicates = array();

foreach ($boxnumber as $val)
if ( $val != "" )
  mysql_select_db($database_logistor, $logistor);
  $sql = "SELECT custref FROM boxes WHERE custref='$val' and status = 'In'";
  $qry = mysql_query($sql) or die(mysql_error());

  if(mysql_num_rows($qry) < 1)
  $duplicates[] = '[ '.$val.' ]';

Open in new window

Who is Participating?
acbxyzConnect With a Mentor Commented:
If you want to do this in PHP you can use array_unique()
$uniqueboxes = array_unique($boxnumber);
if (count($uniqueboxes) != count($boxnumber)) {
  // there are duplicate boxes typed in
  // if you want to know which:
  $dupinputs = array();
  foreach (array_count_values($boxnumber) as $box => $count) {
    if ($count > 1) {
      $dupinputs[] = $box;
  // since array_diff() ignores duplicate values on input array this doesn't work
  // $dupinputs = array_diff($boxnumber, $uniqueboxes);

Open in new window

peter_coopAuthor Commented:
perfect. thank you
Question has a verified solution.

Are you are experiencing a similar issue? Get a personalized answer when you ask a related question.

Have a better answer? Share it in a comment.

All Courses

From novice to tech pro — start learning today.