Teach you to use PHP to implement multi-level tree menu function

//Tree directory structure template program
//Menu catalog field description:
//menu_id menu item id
//menu menu name
//menu_grade Menu level 1 is the main menu and 2 is the secondary menu.....
//menu_superior Previous menu id number

function my_menu($menu_content,$i,$menu_grade_temp,$menu_superior_temp)
{​​
global $php_SELF;
$temp1=$menu_grade_temp+1;
$menu_superior_temp_array=split("/",$menu_superior_temp);
for ($t=0;$t<$i;$t++)
                                                               $menu_array=split("/",$menu_content[$t]);      
If(($menu_array[2]==$menu_grade_temp)&&($menu_array[3]==$menu_superior_temp_array[$menu_grade_temp-1]))
                                                                     for($p=1;$p<=$menu_grade_temp;$p++){echo " ";}
         $temp3=$menu_superior_temp_array;                                        $temp3[$menu_grade_temp]=$menu_array[0];                                        $temp2=implode("/",$temp3);                         If ($menu_array[0]==$menu_superior_temp_array[$temp1-1])
                                                                             $temp5=$temp1-1;                                                        $temp3[$menu_grade_temp]="";                                                   $temp6=implode("/",$temp3);                                              echo "$menu_array[1]
"; ​
             my_menu($menu_content,$i,$temp1,$temp2);                                                                                                                           else
                                                                             $temp3[$menu_grade_temp+1]="";                                                $temp6=implode("/",$temp3);                                              echo "$menu_array[1]
";                                                                                                                                                        }
}
// Connect to MySQL database
$db_host="localhost";
$db_user="dkj";
$db_passWord="123";
$db_name="test";
Mysql_connect($db_host,$db_user,$db_password);
Mysql_select_db($db_name);

//Get data from database
$query_string="select * from menu order by menu_grade";
$db_data=mysql_query($query_string);

//First execution of initialization
if ($menu_grade_temp=="")
{​​
$menu_superior_temp=0;
}

//Read all the information into the array and count the number of arrays
$i=0;
while (list($menu_id,$menu,$menu_grade,$menu_superior)=mysql_fetch_row($db_data))
{​​
$menu_content[$i]=$menu_id."/".$menu."/".$menu_grade."/".$menu_superior;
$i++;
}
my_menu($menu_content,$i,1,$menu_superior_temp);

/* Attached database structure and simulation data
# phpMyAdmin MySQL-Dump
#
# Host: localhost Database: test
#------------------------------------------------ -------
​
#
# Structure of data table 'menu'
#

CREATE TABLE menu (
menu_id int(11) NOT NULL auto_increment,
menu varchar(20) NOT NULL,
menu_grade int(11) NOT NULL,
menu_superior int(11) NOT NULL,
UNIQUE menu_id (menu_id)
);

#
# Export the following database content 'menu'
#

INSERT INTO menu VALUES('1', 'Computer', '1', '0');
INSERT INTO menu VALUES('2', 'Programming', '2', '1');
INSERT INTO menu VALUES('3', 'Network', '2', '1');
INSERT INTO menu VALUES('4', 'PHP and MySql', '3', '2');
INSERT INTO menu VALUES('5', 'C language', '3', '2');
INSERT INTO menu VALUES('6', 'Webpage Production', '3', '3');
INSERT INTO menu VALUES('7', 'TCP, ip protocol', '3', '3');
INSERT INTO menu VALUES('8', 'Math', '1', '0');
INSERT INTO menu VALUES('9', 'Advanced Mathematics', '2', '8');
INSERT INTO menu VALUES('10', 'Linear Algebra', '3', '9');
INSERT INTO menu VALUES('11', 'Discrete Mathematics', '3', '9');
INSERT INTO menu VALUES('12', 'Elementary Mathematics', '2', '8');
INSERT INTO menu VALUES('13', 'Literature', '1', '0');
INSERT INTO menu VALUES('14', 'Chinese Literature', '2', '13');
INSERT INTO menu VALUES('15', 'php', '4', '4');
INSERT INTO menu VALUES('16', 'mysql', '4', '4');
*/
?>

The above has introduced how to use PHP to implement the multi-level tree menu function, including various aspects. I hope it will be helpful to friends who are interested in PHP tutorials.