Question

I have this select:

<select id="mymenu" name="id" onchange="getID()">
    <option></option>
    <option value="1">A</option>
    <option value="2">B</option>
    <option value="3">C</option>
</select>

I want to get the value from mymenu to use it in another select in the same form. I searched the ‘net and found that I should use onchange.

<select name="uid">
    <option></option>
<?
$sql = mysql_query("Select * from $table WHERE id = '$ch_id'");
while ($row = mysql_fetch_array($sql)) {
?>
    <option value="<? echo $row['unit_id']; ?>"><? echo $row['unit_name'];?></option>
<?
}
?>
</select>

This is the getID() function:

<script type="text/javascript">
function getChapterID(){ //run some code when "onchange" event fires
var selectmenu=document.getElementById("mymenu")
<?$ch_id?> = this.options[this.selectedIndex].value
}
</script>

Answer 1

google “ajax php select menu”, the first example here: http://www.w3schools.com/php/php_ajax_database.asp

explains the process…

Beware the w3 demo though, it does not sanitize $_GET[] variable, and is wide open to a sql injection.