Starting from jQuery 1.9, $.browser is no longer supported to detect the nrpwser type and version. The substitute is $.support. In the newer jQuery 2.x versions, IE 6/7/8 are also not supported. If users want to support IE 6/7/8, they must use jQuery 1.9. If you want to fully support IE and want to use jQuery 1.9 and jQuery 2.0, the official solution is:<!--[if lt IE 9]> <script src='jquery-1.9.0.js'></script><![endif]--><!--[if gte IE 9]> <script src='jquery-2.0.0.js'></script><![endif]-->For the long run, this can help in browser feature ...