dynamically update drop down

0
votes

I have a mysql table subjects(subject_id, faculty_id)

I have a drop down that populates subject_id from this table. When a user selects subject_id "1" would like a sql query to select all faculty_id from the same table and update a second drop down where subject_id="selected drop down subject_id"

how can i do this?

Thanks,

2
phpmysqldrop-down-menu
you should use ajax. try looking at jQuery or ExtJS frameworks, they can be useful for you - k102
About how many subjects to we talk? For low amounts of data, you can do this within JS itself. - ty812
i have a lot of datat stored in mysql which needs to be populated into drop down, so i cant use js or hard code it into html - ABI

2 Answers

1
votes

Are you trying to replicate this model? => http://www.plus2net.com/javascript_tutorial/dropdown-list-demo.php

If so, the solution is here => http://www.plus2net.com/javascript_tutorial/dropdown-code.php

Google is your friend : 2 dropdown list mysql update. The second result is the ressource

0
votes

The best way to do this is to use ajax. This is a very simple way to do it, using jQuery :

index.php

   <html>
        <head>
             <script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.6.2/jquery.min.js"></script>
             <!-- here come the following of your page... -->
        </head>
        <body>
             <!-- Your body... -->
             <select name="subject_id" id="subject_id">
             <?php
             // Saying that $list is the list of users from mysql
             foreach ($list as $user) {
             ?>
                  <option value="<?php echo $user; ?>"><?php echo $user; ?></option>
             <?php
             }
             ?>
             </select>

             <select name="sub_select" id="sub_select">
             </select>

             <script type="text/javascript">
             $(document).ready(function () {
                  $('#subject_id').change(function () {
                       $('#sub_select').load('subselect.php?id=' + $('#subject_id').val());
                  }
             }
             </script>
         </body>
    </html>

And the file used to retrieve datas (note : no html, head or body tags here) :

subselect.php

<?php
    $id = (int) $_GET['id'];

    // This is where you do the where subject_id="selected drop down subject_id" sql query
    $list = my_function_to_get_datas($id);
    foreach ($list as $option) {
?>
<option value="<?php echo $option; ?>"><?php echo $option; ?></option>
<?
    }
?>

I didn't test it but it's the idea.