Make JSON.stringify not quote non-ASCII characters. Fix bug 855.

src/json.js

 // Copyright 2009 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 50 matching lines @@
 function JSONParse(text, reviver) {
   var unfiltered = ParseJSONUnfiltered(text);
   if (IS_FUNCTION(reviver)) {
     return Revive({'': unfiltered}, '', reviver);
   } else {
     return unfiltered;
   }
 }
 
 var characterQuoteCache = {
+  '\b': '\\b',  // ASCII 8, Backspace
+  '\t': '\\t',  // ASCII 9, Tab
+  '\n': '\\n',  // ASCII 10, Newline
+  '\f': '\\f',  // ASCII 12, Formfeed
+  '\r': '\\r',  // ASCII 13, Carriage Return
   '\"': '\\"',
-  '\\': '\\\\',
-  '/': '\\/',
-  '\b': '\\b',
-  '\f': '\\f',
-  '\n': '\\n',
-  '\r': '\\r',
-  '\t': '\\t',
-  '\x0B': '\\u000b'
+  '/': '\\/'
 };
 
 function QuoteSingleJSONCharacter(c) {
   if (c in characterQuoteCache) {
     return characterQuoteCache[c];
   }
   var charCode = c.charCodeAt(0);
   var result;
   if (charCode < 16) result = '\\u000';
   else if (charCode < 256) result = '\\u00';
   else if (charCode < 4096) result = '\\u0';
   else result = '\\u';
   result += charCode.toString(16);
   characterQuoteCache[c] = result;
   return result;
 }
 
 function QuoteJSONString(str) {
-  var quotable = /[\\\"\x00-\x1f\x80-\uffff]/g;
+  var quotable = /[\\\"\x00-\x1f]/g;
   return '"' + str.replace(quotable, QuoteSingleJSONCharacter) + '"';
 }
 
 function StackContains(stack, val) {
   var length = stack.length;
   for (var i = 0; i < length; i++) {
     if (stack[i] === val) {
       return true;
     }
   }
@@ skipping 150 matching lines @@
 }
 
 function SetupJSON() {
   InstallFunctions($JSON, DONT_ENUM, $Array(
     "parse", JSONParse,
     "stringify", JSONStringify
   ));
 }
 
 SetupJSON();