[Resolved] Field Validation

[chr158]

Does anybody know how I can validate a field entry when submitting a form?

I have a simple form that uses a lookup to determine the value of a particular field. This is working perfect and the fields value is therefore a valid value.

This field can not be readonly and so therefore the user is still able to enter a free form text, and the update of my table proceeds. I need that field to be checked so that its value matches a DB value that I have in my lookup table.

Cheers

[ir4z0r]

why can't the field not be readonly?
<input name="output" readonly>

[chr158]

Mainly because the user may know which countries exist in the lookup and therefore to save a click they can enter it manually rather than looking it up.

[ir4z0r]

well, I guess the only possibility is to perform another query in the
script which receives the form data.

$res = mysql_query("SELECT * FROM lookup WHERE country='" . $_POST['country'] . "'");
if (mysql_num_rows($res) > 0)
{
  echo "field valid.";
}
else
{
  // return to form and display a message
}