intervalle et rendu html

    <?php foreach($categories as $k=>$v): ?>
    <tr>

        <td>
            
        <?php 
                   if ($levelPrevious < $v['Category']['level']) {
                    echo str_repeat('<ul>', $v['Category']['level'] - $levelPrevious);
                    $prevpass = $levelPrevious;
                    $levelPrevious=$v['Category']['level'];
                    
                    echo '--'.$v['Category']['name'].' ('.$prevpass.' < '.$levelPrevious.')<br />';
             }
            elseif($levelPrevious > $v['Category']['level']){
                    $r .= str_repeat('</ul>', ++$levelPrevious - $v['Category']['level']);
                    $prevpass = $levelPrevious;
                    $levelPrevious=$v['Category']['level'];
                    
                    echo '--'.$v['Category']['name'].' ('.$prevpass.' > '.$levelPrevious.')<br />';
             }
            else{
                    $prevpass = $levelPrevious;
                    echo '--'.$v['Category']['name'].' ('.$prevpass.' < / > '.$levelPrevious.')<br />';
                    
                    $levelPrevious=$v['Category']['level'];
            }
<?php endforeach; ?>
        ?>

<?php

$sql="SELECT * FROM table";
$res=mysql_query($sql);
while($data=mysql_fetch_array($res)){
	$rec[]=$data;
}

function generate_tree_list($arr, $parent = 0){
	$has_children = false;
  	foreach($arr as $key => $value){
    	if ($value['parent_id'] == $parent){
      		if ($has_children == false){
        		$has_children = true;
        		echo '<ul>';
      		}
      		echo '<li>' . $value['name'];
      		echo '<a href="#">Delete</a>';
			echo '<a href="#">Edit</a>';
			echo '<a href="#">On/Off</a>';
	  		unset($arr[$key]);
	  		generate_tree_list($arr, $value['id']);
      		echo '</li>';
    	}
  	}
  	if ($has_children === true) echo '</ul>';
}

function generate_tree_table($arr, $parent = 0,$level = 0){
	$has_children = false;
  	foreach($arr as $key => $value){
    	if ($value['parent_id'] == $parent){
      		if ($has_children == false){
        		$has_children = true;
        		$level++;
      		}
      		echo '<tr>';
			echo '<td style="padding-left:'.(20*($level)).'px;">'. $value['name'].'</td>';
      		echo '<td><a href="#">On/Off</a></td>';
			echo '<td><a href="#">Edit</a></td>';
			echo '<td><a href="#">Delete</a></td>';
			echo '</tr>';
	  		unset($arr[$key]);
	  		generate_tree_table($arr, $value['id'],$level);
    	}
  	}
}

echo '<div style="width:500px;border:1px solid #aaa;">';
echo generate_tree_list($rec);
echo '</div>';

echo '<table border="1" cellpadding="5">';
echo generate_tree_table($rec);
echo '</table>';

?>

<?php 

$a = array(
	array("parent1",array(
		array("enfant1",array()),
		array("enfant2", array(
			array("enfant21",array())
		)),
		array("enfant3",array())
	)),
	array("parent2", array())
);

function afficheHierarchie($array){
	static $level = -1;
	
	$level ++;
	foreach($array as $element){
		for($i=0;$i<$level;$i++)
			echo "--";
		echo $element[0] . "<br />";
		afficheHierarchie($element[1]);
	}
	$level--;
	
}

afficheHierarchie($a);

?>