Get complete form data as array and json stringify it.
var formData = JSON.stringify($("#myForm").serializeArray());
You can use it later in ajax. Or if you are not using ajax; put it in hidden textarea and pass to server. If this data is passed as json string via normal form data then you have to decode it using json_decode. You’ll then get all data in an array.
$.ajax({
type: "POST",
url: "serverUrl",
data: formData,
success: function(){},
dataType: "json",
contentType : "application/json"
});