Write down the properties of JSON Web Token. 15. Explain the concept of virtual DOM in react. 16. How JSX is converted into JavaScript code? 17. Suppose we have following ajax requests prepared in jQuery. Each request send two numbers to back end with different configurations. You are to make express end points to handle each request. Suppose express is already setup and server is created with a variable app. 1. jsx $.ajax({ method: "GET", url: "api/calculator/add", data: {a: 5, b: 6}, success: function(res) { console.log(res); // 11 should be printed }, }); b. jsx $.ajax({ method: "GET", url: "api/calculator/add" + 5 + "/" + 6, data: {a: 5, b: 6}, success: function(res) { console.log(res); // 11 should be printed }, }); c. jsx $.ajax({ method: "GET", url: "api/calculator/add", data: {a: "whoala", b: 6}, success: function(res) { console.log(res); // response should be an error message }, }); 18. Make an HTML form with id=myForm to submit email and password to express. But instead of form submission stop its submission and make an AJAX call only if the user has given email and password both. Starter code is given below: jsx $(function(){ $("#myForm").on("submit", function(e){ e.preventDefault(); //write your code here at the back of this sheet }) })