Php實現Js的escape方法

//php function
   function escape($string) {                $n = $bn = $tn = 0;                $output = '';                $special = "-_.+@/*0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";                while($n < strlen($string)) {                        $ascii = ord($string[$n]);                        if($ascii == 9 || $ascii == 10 || (32 <= $ascii && $ascii <= 126)) {                                $tn = 1;$n++;                        } elseif(194 <= $ascii && $ascii <= 223) {                                $tn = 2;$n += 2;                        } elseif(224 <= $ascii && $ascii <= 239) {                                $tn = 3;$n += 3;                        } elseif(240 <= $ascii && $ascii <= 247) {                                $tn = 4;$n += 4;                        } elseif(248 <= $ascii && $ascii <= 251) {                                $tn = 5;$n += 5;                        } elseif($ascii == 252 || $ascii == 253) {                                $tn = 6;$n += 6;                        } else {                                $n++;                        }                        $singleStr = substr($string,$bn,$tn);                        $charVal = bin2hex(iconv('utf-8', 'ucs-2', $singleStr));                        if(base_convert($charVal, 16, 10) > 0xff) {                             if (!preg_match("/win/i", PHP_OS))                                $charVal = substr($charVal, 2, 2).substr($charVal, 0, 2);                                                        $output .= '%u' . $charVal;                        }                         else {                                if(false !== strpos($special, $singleStr))                                     $output .= $singleStr;                                                               else                                      $output .="%" . dechex(ord($string[$bn]));                        }                  $bn = $n;                }return $output;}