JSON Web Token (JWT) is an open standard (RFC 7519) that defines a compact and self-contained way for securely transmitting information between parties as a JSON object. This information can be verified and trusted because it is digitally signed. JWTs can be signed using a secret (with HMAC algorithm) or a public/private key pair using RSA. 

JSON Web Token is a security token which acts as a container for claims about the user, it can be transmitted easily between the Authorization server (Token Issuer), and the Resource server (Audience), the claims in JWT are encoded using JSON which make it easier to use especially in applications built using JavaScript. 

Unexpected token o in JSON at position 1
 at JSON.parse

Expression<Func<Book, bool>> expression = x => x.Code > 2 && x.Code < 5;
var expressionSerializer = new Common.ExpressionSerializer();
var xml = expressionSerializer.Serialize(expression);
var xmlToJson = JsonConvert.SerializeObject(xml);
var xmlObject = JsonConvert.DeserializeObject<XElement>(xmlToJson);
var exp2 = expressionSerializer.Deserialize(xmlObject) as Expression<Func<Book, bool>>;

public void ProcessRequest (HttpContext context) {
        new InMemoryPdfReport().CreatePdfReport();
    }

 $(function() {
            $("#Button3").click(function () {
                //var url = "Default.aspx";
                //$(location).attr('href', url);
                $.ajax({
                    url: 'Handler.ashx',
                    contentType: "application/json; charset=utf-8",
                   dataType: "json",
                    success: function (data) {
                       
                    }
                });
            });
        });