Why this code cannot join the link

Why can't I add a link to this code?

 
  <title>New Document</title>
 

 
  
 $link = mysql_connect (' 127.0.0.1 ', ' root ', ' 520928 ') or Die (Mysql_error ());//Connect to database server
mysql_select_db (' test ');//Select Database
Mysql_set_charset (' UTF8 ');//Set character encoding
 
$sql = "SELECT * from Wxtree";//Query classification table
$result = mysql_query ($sql);
$tree = Array ();//Initialize an array
while ($row = Mysql_fetch_assoc ($result))
{
$tree [$row [' FID ']][$row [' id ']] = $row [' cat_name '];//creating a categorical array
}
Mysql_close ($link);//Close Database
  
Print_r ($tree [02]);
Echo '-------------------------------------------'. "\ n";
 
Recursive functions
  
function for_category ($arr = Array (), $arr 2)
{
echo "
 
 

  
  

    "; 
   
 foreach ($arr as $k = + $v) 
   
 { 
   
 if (isset ($arr 2[$k) && is_array ($arr 2[$k] ) 
   
 { 
   
 echo " 
   
 $k $v         w3school&nbsp Add to edit  &nbsp delete   "; 
 
   
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