get form data as json

form.js

/**
 * Extract the value of all form fields specified in fields.
 **/
$.fn.getFormData = function (fields) {
  var res = {};
  for (var i = 0; i < fields.length; i++) {
    var field = fields[i];
    res[field] = $(this).find("[name=" + field + "]").val();
  }
  return res;
};

/**
 * Returns all the input fields of the form.
 **/
$.fn.getAllFormData = function () {
  var res = {};

  $(this).find("input, textarea, select, checkbox").each(function (idx, elt) {
    elt = $(elt);
    res[elt.attr("name")] = elt.val();
  });

  return res;
};