Get ASP.NET Session ID using jQuery

You cannot do this only in jQuery, since it is only on the client side and cannot talk to the server to get sessionID.

The workaround is to create a web service that returns a session identifier in XML / JSON format that you can call from an AJAX request in jQuery.

Something like that:

$.ajax({
    url: "/mywebservice.asmx",
    dataType: "json",
    success: function(data) {
        var sessionId = data.sessionId; // This would be determined by your server-side implementation
        // do something with the sessionId...
    }
});