PHP获得最高动态选择的值

Question

I have a series of selects that contain world regions.

For instance select r0 would contain

Africa
North America
Europe

When the user selects North America, a new select named r1 would appear with the following values:

Canada
United States
Mexico

Then the user would select US, r2 would appear with the states and so on.

As the data structure allows, currently, there can be up to 5 boxes (r0-r4)

I am trying to figure out how in php I can determine that there are 4 or 5 selects, and save that value of the highest number select to the database.

Am I going at this the wrong way?

Currently, I don't have any code written, because I'm not sure how to test the range of the $_POST["r#"] arrays, but was thinking something along the lines of:

<?php
$i = 0;
while (isset($_POST['r'.$i])) {
    $highest_value = $_POST['r'.$i];
    $i++;
}

?>

is there a better way?

Answer 1

I will try this :

$Value = null;
for ($i = 5; $i >= 0; $i--) {
    if(isset($_POST['r'.$i]) AND $_POST['r'.$i]){
        $Value = $_POST['r'.$i];
        break;
    }
}

I did not test it out.