$.ajax({ 
  type: "POST", 
  url: "WebService.asmx/AddVisitor",
  data: "{'fname':'dave', 'lname':'ward'}", 
  contentType: "application/json; charset=utf-8", 
  dataType: "json"
});

I have an Asp.Net WebMethod that takes a firstName, lastName.....as a parameter, how do I send that stuff to that method using the JQuery Ajax method. if i hardcode the above it works without any problem

but if i pass dynamic it fails

var firstName = $("[id$='txtFirstName']");
var lastName = $("[id$='txtLastName']");

//data: "{'firstName':'Chris','lastName':'Brandsma'}"<br>

data: "{'firstname':'" + escape(firstName.val()) + "','lastName':'" + escape(lastName.val()) + "'}",

my WebMethod looks like this

[WebMethod]
public bool AddVisitor(string firstName, string lastName)
{
    return true;
}

what wrong here? i have tried with eval and escape none of that works.

Thanks for any help.