key/value form2json - http://codepen.io/wookiecooking/pen/tphAF

keyval.js

// require('jquery')

$( "form" ).submit(function( event ) {
  var ara = {}
  
  $('form .set').each(function(){
    var data = $(this).find("input")
    ara[data[0].value] = data[1].value;
  })
  
  $('.result p').text(JSON.stringify(ara))
  
    if($('.list div').length >= 5) {
      alert('to many to ajax');
    }
 
    event.preventDefault();
 });

// add new input set
$('.add').click(function(event){
  if($('.list div').length >= 5) {
    return alert('to many');
  }
 $('.template').clone(true)
   .removeClass('template')
   .appendTo( ".list" );
  event.preventDefault();
})

// remove input set
$('.set .remove').click(function(event){
  $(this).parent('.set').remove();
  event.preventDefault();
})

style.css

.template {display:none};

template.html

<a href="#" class="add">Add New</a>
<div class="template set">
    <input type="text" placeholder="key" name="key" value="">
    <input type="text" placeholder="value" name="value" value="">
    <a href="#" class='remove'> Remove</a>
  </div>

<form>
  <div class="list">
  <div class="set">
    <input type="text" placeholder="key" name="key" value="">
    <input type="text" placeholder="value" name="value" value="">
    <a href="#" class='remove'> Remove</a>
  </div>
  </div>
  <button type="submit"> Click </button>
</form>
<div class="result"><h2>result</h2><p></p></div>