Javascript + Php + Javascript

[rogernem]

Here is my code:

<script language="javascript">
function show_list(){
var val = document.myform.master.options[document.myform.master.selectedIndex].value;

  if(val==19){ 
  <?
  $sql = 'select * from table where id=19 ORDER BY id ASC'; 
  $res = mysql_query($sql);
  $tot = mysql_num_rows($res);
  for($i=0;$i<$tot;$i++){
    $r = mysql_fetch_array($res);
  ?>
  document.myform2.master.options[<?=$i?>]=new Option("<?=$r[city]?>", <?=$r[id]?>, true, false)
  <? } ?>
  }
}
</script>

The problem is that I´m setting the id value and I dont want to do that.
How can I put the javascript value (val) into this php line below?
sql = 'select * from table where id=19 ORDER BY id ASC';

I´d like something like this:
sql = 'select * from table where id='+val+' ORDER BY id ASC';

[PeejAvery]

Remember that PHP is server-side and therefore is interpreted before your JavaScript. That means you have to create the JavaScript and then send it to the server.

You can do this through 2 options, using a $_POST form or putting it in the url and using $_GET.

<?php
$id = @$_GET['id'];

$sql = "SELECT * FROM `table` WHERE `id` = '$id' ORDER BY `id` ASC";
?>

[danbopes]

$id = @$_GET['id'];

Whats with the @ symbol? If id isnt set, then $id will just become nothing.

[PeejAvery]

Whats with the @ symbol? If id isnt set, then $id will just become nothing.

And will also cause an error to be written to the log. I use the @ to avoid excess logging of something I already know.

[danbopes]

And will also cause an error to be written to the log. I use the @ to avoid excess logging of something I already know.

I never knew it logged empty variables...wait where? on the server(like the error_log file), cause I never seen it log any of this anywhere.

[PeejAvery]

In the PHP folder on the server is file named error.log. All errors are written there. If you call $_GET['var']; and there is not [u]var=[/url] in the URL line, you will get a silent log error.