Query database onchange of dropdown menu, then output to form

Question

Hi I'm performing the following query on a database which is getting me a dropdown menu. I want this to query the database onchange so that I can use that information in another form.

$dropdown_sql="SELECT product_id, product_name, unit_price, unit_quantity, in_stock FROM products";
$dropdown_result=mysql_query($dropdown_sql);

$options="";

while ($row=mysql_fetch_array($dropdown_result)) {
    $id=$row["product_id"];
    $product_name=$row["product_name"];
    $unit_price=$row["unit_price"];
    $unit_quantity=$row["unit_quantity"];
    $in_stock=$row["in_stock"];
    $options.="<OPTION VALUE=\"$id\">$product_name - $unit_quantity";
}
?>

The dropdown menu:

<SELECT NAME=product_name onchange="dropdown_change()">
<OPTION VALUE=0>Select a food
    <?php echo $options ?>
    </SELECT>

I can detect the change in javascript

function dropdown_change()
{
  alert("hello")
}

BUT I can't get the information from that point, and the I can't put it in the form. Please help.

To communicate between your onchange javascript and the php code which queries database, you need either post the values on change, or use Ajax calls. — janenz00
– janenz00, Commented Jul 16, 2013 at 1:15

Mihai Iorga · Accepted Answer · 2011-09-08 08:39:06Z

1

Add this in select dropdown.

change the select form with:

<select name="product_name" onchange="dropdown_change(this)">
...................
</select>

<script type="text/javascript">
    function dropdown_change(el){
        var elValue = el.value;
    }
</script>

Test: JSFiddle

answered Sep 8, 2011 at 8:39

Mihai Iorga

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Comments

Shameer · Accepted Answer · 2011-09-08 09:04:04Z

1

If you are using jquery library,

function dropdown_change(){
    var val = $("select[name=product_name]").val();
    $.ajax({
        data : {key:val},
        url : 'your_url',
        success : function(msg){
            // do what ever you want
        }
    })
}

answered Sep 8, 2011 at 9:04

Shameer

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