Question

I’m trying to get an already populated dropdown menu to change focus on it’s selection once I do a _REQUEST for an ID from another page – the ID will correlate to the ID of the item in the database.

So here’s the request

$product_id_request=$_REQUEST["product_id"];

and the drop down menu code:

$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";
}
?>

And the dropdown

<OPTION VALUE=0>Select a food
<?php echo $options ?>
</SELECT>

Answer 1

In your while() loop, set the selected attribute on your OPTION tag. Something like this:

$selected = ($id == $product_id_request) ? ' selected="selected"' : '';
$options .= "<OPTION VALUE=\"$id\"$selected>$product_name - $unit_quantity</OPTION>";

You should also close the option tag.

To check for the presence of the ID, edit the top, like this:

$product_id_request = (isset($_REQUEST["product_id"])) ? $_REQUEST['product_id'] : 0;

The default value will be 0 if it is not supplied.