<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>Untitled</title>
</head>
<body>
<form action="unaprueba.php" name='prueba' method='POST'>
1<input type="checkbox" name='caja[]'/><br/>
2<input type="checkbox" name='caja[]'/><br/>
3<input type="checkbox" name='caja[]'/><br/>
4<input type="checkbox" name='caja[]'/><br/>
5<input type="checkbox" name='caja[]'/><br/>
6<input type="checkbox" name='caja[]'/><br/>
7<input type="checkbox" name='caja[]'/><br/>
8<input type="checkbox" name='caja[]'/><br/>
9<input type="checkbox" name='caja[]'/><br/>
<input type='submit' value='validar'>
</form>
<?php
if(isset($_POST['caja'])){
$x = $_POST['caja'];
$i = 0;
$n = count($x);
while ($i < $n){
echo $x[$i], "<br>";
$i++;
}
}
?>
</body>
</html>