Dynamic dropdowns using jQuery and PHP

	Root <select name="root" id="root"></select>
	Sub1 <select name="sub1" id="sub1"></select>
	Sub2 <select name="sub2" id="sub2"></select>

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<script>
$(function() {
	var root = document.getElementById('root');
	var sub1 = document.getElementById('sub1');
	var sub2 = document.getElementById('sub2');
	loadDD(root, false, false);
	
	$('select').change(function() {
		if (this.id == 'root') {
			sub1.value = sub2.value = '';
			loadDD(root, sub1, false)
		}
		else if (this.id == 'sub1') {
			sub2.value = '';
			loadDD(root, sub1, sub2);
		}
	});
});
function loadDD(root, sub1, sub2)
{
	$.ajax({
		url: 't2884.php',
		data: {
			root: root.value || '',
			sub1: sub1.value || ''
		}
	}).then(function(resp) {
		if (root.value) {
			if (sub1.value) {
				sub2.innerHTML = resp;
			}
			else {
				sub1.innerHTML = resp;
			}
		}
		else {
			root.innerHTML = resp;
		}
	});
}
</script>

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<?php
$path = 't2884/';

$root = isset($_GET['root']) ? $_GET['root'] : false;
$sub1 = isset($_GET['sub1']) ? $_GET['sub1'] : false;

if ($root) $path .= "{$root}/";
if ($sub1) $path .= "{$sub1}/";
$path .= '*';

$dirs = array_filter(glob($path), 'is_dir');
foreach($dirs as $f) {
	$file = basename($f);
	echo <<< OPTION
	<option value="{$file}">{$file}</option>
OPTION;
}

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