code: function (form) {
              var elements = form.elements, params = [], element, name, value;
              for (var i = 0, len = elements.length; i < len; i++) {
                  element = elements[i];
                  if (this._isSerializable(element)) {
                      name = encodeURIComponent(element.name);
                      value = encodeURIComponent(element.value.replace(/\r?\n/g, "\r\n"));
                      params.push(name + "=" + value);
                  }
              }
              return params.join("&").replace(/%20/g, "+");
          }
docs: Turn an HTML form element into a string that contains the list of name-value pairs of all relevant elements
  of the form. For example, the following form
  
  <pre>
  &lt;form id=&quot;myForm&quot;&gt;
  &lt;input type=&quot;text&quot; name=&quot;firstname&quot; value=&quot;Colin&quot;&gt;
  &lt;input type=&quot;text&quot; name=&quot;lastname&quot; value=&quot;Pitt&quot; disabled&gt;
  &lt;input type=&quot;date&quot; name=&quot;birth&quot; value=&quot;2012-04-04&quot;
  &lt;input type=&quot;text&quot;&gt;
  &lt;input type=&quot;file&quot; name=&quot;picture&quot; /&gt;
  &lt;input type=&quot;submit&quot; name=&quot;submit&quot;/&gt;
  &lt;input type=&quot;checkbox&quot; name=&quot;vehicle&quot; value=&quot;Bike&quot; checked /&gt;
  &lt;/form&gt;
  </pre>
  
  yields
  
  <pre>
  firstname
  =Colin&amp;birth=2012-04-04&amp;vehicle=Bike
  </pre>
  
  This method can be useful when you want to send the form information as data of an ajax call
  @param {HTMLElement} form
  @return {String}