$('#btnLogin').click(function () {
    $.ajax({
        // Post username, password & the grant type to /token
        url: '/token',
        method: 'POST',
        contentType: 'application/json',
        data: {
            username: $('#txtUsername').val(),
            password: $('#txtPassword').val(),
            grant_type: 'password'
        },
        //response(Access Token) stores inside session storage of Client browser.
        success: function (response) {
            sessionStorage.setItem("accessToken", response.access_token);