var keyStr = "ABCDEFGHIJKLMNOP" + 
              "QRSTUVWXYZabcdef" + 
              "ghijklmnopqrstuv" + 
              "wxyz0123456789+/" + 
              "="; 

function native2ascii(strNative) { 
     var output = ""; 
     for (var i=0; i<strNative.length; i++) { 
         var c = strNative.charAt(i); 
         var cc = strNative.charCodeAt(i); 
         if (cc > 0xff) 
           output += "\\u" + toHex(cc >>  8 ) + toHex(cc & 0xff); 
         else 
           output += c; 
     } 
     return output; 
} 

var hexChars = "0123456789ABCDEF"; 
function toHex(n) { 
     var nH = (n >> 4) & 0x0f; 
     var nL = n & 0x0f; 
     return hexChars.charAt(nH) + hexChars.charAt(nL); 
} 

function ascii2native(strAscii) { 
     var output = ""; 
     var posFrom = 0; 
     var posTo = strAscii.indexOf("\\u", posFrom); 
     while (posTo >= 0) { 
         output += strAscii.substring(posFrom, posTo); 
         output += toChar(strAscii.substr(posTo, 6)); 
         posFrom = posTo + 6; 
         posTo = strAscii.indexOf("\\u", posFrom); 
     } 
     output += strAscii.substr(posFrom); 
     return output; 
} 

function toChar(str) { 
     if (str.substr(0, 2) != "\\u") return str; 

     var code = 0; 
     for (var i=2; i<str.length; i++) { 
         var cc = str.charCodeAt(i); 
         if (cc >= 0x30 && cc <= 0x39) 
             cc = cc - 0x30; 
         else if (cc >= 0x41 && cc <= 0x5A) 
             cc = cc - 0x41 + 10; 
         else if (cc >= 0x61 && cc <= 0x7A) 
             cc = cc - 0x61 + 10; 

         code <<= 4; 
         code += cc; 
     } 

     if (code < 0xff) return str; 

     return String.fromCharCode(code); 
}