return ex instanceof SyntaxError; 
return ex.name == "SyntaxError"; 
  function isInvalidSyntax(a) {    // FIXME: bug 393206    return true;    try {      JSON.fromString(a);      return false;    } catch (ex) {      return ex instanceof SyntaxError;    }  }
5872	/local1/tlutelli/issta_data/temp/all_js/javascript/2007_temp/2007/5872/06deeccfe641bc21564cf4382bfa041e711a84ae/test_json.js/buggy/js/src/xpconnect/tests/unit/test_json.js