[jQuery] Ajax

<script>

  $('#elementid').click(function(){

    $.ajax({
        url:"api-url",
        type:"POST",
        dataType:"json",
        data: {a:1, b:2}
    })
    .done((data,status,jqXHR) => {
      console.log(data);

      $("#elementid").text(data["rootobj"]["childobj"]);
    })
    .fail((data) => {
      console.log(data.responseText); 
    })
    .always((data) => {
      console.log(data);
    });
  });
</script>