User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-GB; rv:1.9.1b2) Gecko/20081201 Firefox/3.1b2 Build Identifier: Mozilla/5.0 (X11; U; Linux i686; en-GB; rv:1.9.1b2) Gecko/20081201 Firefox/3.1b2 When using the library 'Json2.js'¹ the call 'JSON.stringify("some string")' generates an error saying "Invalid argument". This issue does not appear in Firefox 3.0.x. In this example² it first try 'JSON.stringify(["OK"])' which works and then it will try 'JSON.stringify("KO")' which generate the above error. [1] : http://www.json.org/js.html [2] : http://www.gburri.org/bordel/issue%20firefox%203.1/ Reproducible: Always Steps to Reproduce: 1. Use the lib 'json2.js' from http://www.json.org/js.html 2. Call 'JSON.stringify("some string")' Actual Results: Error 'Invalid argument' Expected Results: JSON.stringify("some string") => "\"some string\"" The bug can also be reproduce in a Windows XP system with Firefox 3.1 Beta2