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<?PHP
/*
CREATE TABLE `category` (
  `categoryID` int(10) unsigned NOT NULL auto_increment,
  `categoryParentID` int(10) unsigned NOT NULL default '0',
  `categoryName` varchar(50) NOT NULL default '',
  KEY `cate_id` (`categoryID`)
) TYPE=MyISAM AUTO_INCREMENT=11 ;
#
# 导出表中的数据 `category`
#

INSERT INTO `category` S (1, 0, '一级类别1');
INSERT INTO `category` S (2, 1, '二级类别1');
INSERT INTO `category` S (3, 1, '二级类别2');
INSERT INTO `category` S (4, 1, '二级类别3');
INSERT INTO `category` S (5, 2, '三级类别21');
INSERT INTO `category` S (6, 2, '三级类别22');
INSERT INTO `category` S (7, 2, '三级类别23');
INSERT INTO `category` S (8, 3, 'rfwesdfsd');
INSERT INTO `category` S (9, 4, '54534w43');
INSERT INTO `category` S (10, 5, '66666');
*/
mysql_connect( "localhost", 'root', '' );
mysql_select_db( "test" );
$cate_table = "category";

_GetCategory( $category_id = 0, $depth = 1 )
{
        global $cate_table;

        $sql = "SELECT * FROM $cate_table ORDER BY categoryID DESC";
        $result = mysql_query( $sql );

        while ( $row = mysql_fetch_array( $result ) )
        {
                $array[$row[categoryParentID]][$row[categoryID]]
                = array(
                        'id' => $row[categoryID],
                        'parent' => $row[categoryParentID],
                        'name' => $row[categoryName]
                );
        }

        if ( !isset( $array[$category_id] ) )
        {
                return "";
        }

        foreach( $array[$category_id] AS $key => $category )
        {
                echo " <OPTION =".$category['id']." ";
                if ( $category['parent'] == 0 )
                {
                        echo " class='main' ";
                }
                if ( $depth > 1 )
                {
                        echo ">" . str_repeat( "--", $depth - 1 ) . " " . $category['name'] . "</option>n";
                }
                else
                {
                        echo ">" . $category['name'] . "</option>\n";
                }

                _GetCategory( $key, $depth + 1 );
        }
        unset( $array[$category_id] );
}

?>
<select name="categoryID">
<option selected ="">-------------</option>
<?=_GetCategory();?>
</select>