Unicode value \uXXXX to Character in Javascript

I've never done this before and am not sure why it's outputting the infamous � encoding character. Any ideas on how to output characters as they should (ASCII+Unicode)? I think \u0041-\u005A should print A-Z in UTF-8, which Firefox is reporting is the page encoding.

   var c   = new Array("F","E","D","C","B","A",9,8,7,6,5,4,3,2,1,0);
   var n   = 0;
   var d   = "";
   var o   = "";

   for (var i=16;i--;){
      for (var j=16;j--;){
         for (var k=16;k--;){
            for (var l=16;l--;){

               d =  c[i].toString()
                 +  c[j].toString()
                 +  c[k].toString()
                 +  c[l].toString();

               o += ( ++n + ": " 
                    + d   + " = " 
                    + String.fromCharCode("\\u" + d) 
                    + "\n<br />" );

               if(n>=500){i=j=k=l=0;} // stop early
            }
         }
      }
   }

   document.write(o);