var str = 'A'; 
var val = str.charCodeAt(0); 
var uni = val.toString(16).toUpperCase(); 
$.writeln(uni); 

String.prototype.fill = function(number){var filled ="";for (var i=0;i<number;++i){filled += this;}return filled;} 
String.prototype.padLeft = function(fillc, length) 
        {if (this.length<length){return (fillc.fill(length-this.length)+this).substr(-length);}return this;} 
Number.prototype.padLeft = function(fillc, length) 
    {return this.toString().padLeft(fillc, length);} 
/*string*/ String.prototype.bytesToHexCode=function()  
{ 
    var hexString = ""; 
    for (var i=0; i < this.length; i++)  
    { 
        hexString += this.charCodeAt(i).toString(16).toUpperCase().padLeft("0",2); 
    } 
    return hexString; 
} 

"\u1D538".bytesToHexCode() 
Ergebnis: 1D5338 

/*string*/ String.prototype.toUnicode=function()  
{ 
    var unicodeString = ''; 
    for (var i=0; i < this.length; i++)  
    { 
        var unicode = "\\u" + this.charCodeAt(i).toString(16).toUpperCase().padLeft("0",4); 
        unicodeString += unicode; 
    } 
    return unicodeString; 
} 

"ᵓ8".toUnicode() 
Ergebnis: \u1D53\u0038 

var str = 'A'; 
uni = str.bytesToHexCode(); 
$.writeln(uni); 
// => D835DD38 

var str = 'A'; 
uni = str.toUnicode(); 
$.writeln(uni); 
// => \uD835\uDD38 

"\u1D538" 
Ergebnis: ᵓ8 -> Darstellungsproblem 
"\u1D538".bytesToHexCode() 
Ergebnis: 1D5338 

"\u1D538".toUnicode() 
Ergebnis: \u1D53\u0038 

alert(decimalToHex(0x1D538)); 
function decimalToHex(d, padding) { 
    var hex = Number(d).toString(16); 
    padding = typeof (padding) === "undefined" || padding === null ? padding = 2 : padding; 
 
    while (hex.length < padding) { 
        hex = "0" + hex; 
    } 
 
    return hex; 
} 

function emojiUnicode (emoji) { 
    var comp; 
    if (emoji.length === 1) { 
        comp = emoji.charCodeAt(0); 
    } 
    comp = ( 
        (emoji.charCodeAt(0) - 0xD800) * 0x400 
      + (emoji.charCodeAt(1) - 0xDC00) + 0x10000 
    ); 
    if (comp < 0) { 
        comp = emoji.charCodeAt(0); 
    } 
    return comp.toString("16"); 
}; 

str.charCodeAt(0) 

function emojiUnicode (emoji) { 
    var comp; 
    if (emoji.length === 1) { 
        comp = emoji.charCodeAt(0); 
    } 
    comp = ( 
        (emoji.charCodeAt(0) - 0xD800) * 0x400 
      + (emoji.charCodeAt(1) - 0xDC00) + 0x10000 
    ); 
    if (comp < 0) { 
        comp = emoji.charCodeAt(0); 
    } 
    return comp.toString("16"); 
}; 

$.writeln(char2unicode('A')); 
 
function char2unicode(str) 
{ 
   var comp, 
       uni; 
   if (str.length === 1) 
   { 
      comp = str.charCodeAt(0); 
   } 
   else 
   { 
      comp = ( 
         (str.charCodeAt(0) - 0xD800) * 0x400 + 
         (str.charCodeAt(1) - 0xDC00) + 0x10000 
      ); 
      if (comp < 0) 
      { 
         comp = emoji.charCodeAt(0); 
      } 
   } 
   uni = comp.toString("16").toUpperCase(); 
   while (uni.length < 4) 
   { 
      uni = '0' + uni; 
   } 
   return uni; 
}; 

      comp = (  
         (str.charCodeAt(0) - 0xD800) * 0x400 +  
         (str.charCodeAt(1) - 0xDC00) + 0x10000  
      );