How to Create Dynamicaly 3 interlinked Drop Down List (combo list) in php

[Venter]

i'm Having 3 tables those are like 1.State table 2. District Table 3.college Table
state table
cat_id       state
 1         Andhrapradesh    
 2          Gujarat
 3          Punjab
 4           mumbai
 ---------------
 district Table

 cat_id  d_id      district
  1       1        vizag   
  1       2        eastgadavari
  1       3        hyderabad
  1       4        westgadavari
  --------------------------------------
  college table 
 Cat_id  d_id  c_id   c_name
  1       1     1     vits
  1       1     2     geetham
  1       1     3     anits

  ---------------------------------
  now i want make a 3 dropdown lists from database dynamically.
  any 1 plz help me.
  all the three combo lists are dependent & They are in single Form.
  Thanks to Every1......

[pritaeas]

Start here: http://www.daniweb.com/web-development/php/code/437655/getting-products-details-from-categories-subcategories-with-ajax-call-

[david.leatherman.908]

This can get you started - code for creating State Table - call from body where you want it - the input can be 0 to not select any of the choices or an index value of one of the choices to display pre-selected choice...

function StateDropDown($nSel)
{
    $pick;

    global $db;

    $ret_string = "<select name='StateDropDown'><option value='0'>Select State</option>";

    $query = 'SELECT cat_id, state FROM StateTable';
    $result = mysql_query($query, $db) or die(mysql_error($db));
    while ($rows = mysql_fetch_array($result)) 
    {
    $CAT_ID  = $rows[0];
    $ST_Name = $rows[1];
    if ($nSel == $CAT_ID)
        $pick = " SELECTED ";
    else
        $pick = "";

    $ret_string = $ret_string . "<option value='" . $CAT_ID . "'" . $pick . ">" . $ST_Name . "</option>";
    }
$ret_string = $ret_string . "</select>";
return $ret_string;
}

By using the index of the returned selection, you can similarly fashion (dynamically) the next drop down.

Hope it helps