Post form data to Marketo w/o page reload (JavaScript)

post-no-reload.js

function postToMarketo() {
    
    var form        = $('<form class="marketo-form" method="post" enctype="application/x-www-form-urlencoded" action="http://info.domain.com/index.php/leadCapture/save" id="mktForm_ID" name="mktForm_ID">');
    var inputArr    = {};
    var selectedArr = {};
    var key;
    var inputs      = $('form.leadgen input');
    var selected    = $('form.leadgen option[selected]');
    var iframe      = $('<iframe style="display:none;" id="new-form" src="/marketo_success.html"></iframe>');
   
    // rebuild inputs and append to new form
    inputs.each(function() {
      inputArr[this.id] = $(this).val();
    });

    for(var key in inputArr) {  
      var hiddenField = $("<input>");
      hiddenField.attr({
        type: "hidden",
        name: key,
        value: inputArr[key] 
      });
       form.append(hiddenField);
    }
  
    
    // rebuild dropdown selections and append to new form
    selected.each(function() {
      var parentName  = $(this).parent().attr('name');
      var optionField = $('<select><option>');
      
      optionField.attr('name',parentName);
      optionField.children().attr({
        value: $(this).val(),
        selected: "selected"
      });
      form.append(optionField);
    });
      
    // put form into iframe
    iframe.load(function() {
        iframe.contents().find('body').append(form);
    });

    // put iframe as results
    $('#registration').append(iframe);

  }