PHP mb_ereg_replace not replacing while preg_replace works as intended

Question

I am trying to replace in a string all non word characters with empty string expect for spaces and the put together all multiple spaces as one single space.

Followin

Answer 1

function create_slug_html($string, $ext='.html'){     
   $replace = '-';         
   $string=strtolower($string);     
   $string=trim($string);

    mb_regex_encoding("UTF-8");
    //regex could also be \W
    $string= mb_ereg_replace('[^\w]', ' ', $string);
    $string= mb_ereg_replace('\s+', ' ', $string);

   //remove query string     
   if(preg_match("#^http(s)?://[a-z0-9-_.]+\.[a-z]{2,4}#i",$string)){         
         $parsed_url = parse_url($string);         
         $string = $parsed_url['host'].' '.$parsed_url['path'];         
         //if want to add scheme eg. http, https than uncomment next line         
         //$string = $parsed_url['scheme'].' '.$string;     
   }      
   //replace / and . with white space     
   $string = preg_replace("/[\/\.]/", " ", $string);   

   // $string = preg_replace("/[^a-z0-9_\s-]/", "", $string);  

   //remove multiple dashes or whitespaces     
   $string = preg_replace("/[\s-]+/", " ", $string);   

   //convert whitespaces and underscore to $replace     
   $string = preg_replace("/[\s_]/", $replace, $string);     
   //limit the slug size     
   $string = substr($string, 0, 200);     
   //slug is generated     
   return ($ext) ? $string.$ext : $string; 

}

please check is it ok and support english and unicode