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<p>This is a stripped-down version of the PHP code which implements collapsible
trees on <a href="http://math.arizona.edu/~kerl">my home page</a>.  The source
code is <a href="idxshort.html">here</a>.  Enjoy!

<?php

# ================================================================
# John Kerl
# kerl.john.r@gmail.com
# 2007-05-16
# ================================================================

$usrv = $_GET['v'];
$v = isset($usrv) ? $usrv : 0;

if (is_string($v)) {
	if ($v == 'label1')
		$v = 0x01;
	else if ($v == 'label2')
		$v = 0x02;
	else if ($v == 'label3')
		$v = 0x04;
}

$n01 = $v ^ 0x01;
$n02 = $v ^ 0x02;
$n04 = $v ^ 0x04;

echo "<ul>";

echo "<li> <a href=\"idxshort.php?v=$n01\">Text here</a>";
if ($v & 0x01) {
?>
	<!-- Plain HTML here -->
	<ul>
	<li> Content here
	<li> Content here
	<li> Content here
	</ul>
<?php
}

echo "<li> <a href=\"idxshort.php?v=$n02\">Text here</a>";
if ($v & 0x02) {
?>
	<ul>
	<li> Content here
	<li> Content here
	</ul>
<?php
}

echo "<li> <a href=\"idxshort.php?v=$n04\">Text here</a>";
if ($v & 0x04) {
?>
	<ul>
	<li> Content here
	<li> Content here
	<li> Content here
	<li> Content here
	</ul>
<?php
}

echo "</ul>";

?>

<p> <a href="idxshort.php?v=255">Expand all</a> | <a href="idxshort.php?v=0">collapse all</a>

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