Get array of values from multiple inputs using jQuery

Use jQuery's native serialize function:

var data = $('input[name="additionaltitlename"]').serialize();

docs

The .serialize() method creates a text string in standard URL-encoded notation. It operates on a jQuery object representing a set of form elements.

It's not valid to have two inputs of the same name. If you want to do this, you can use <input name="titles[]">

You can try this:

<input name="titles[]">
<input name="titles[]">
​<button>submit</button>​​​​​​​​​​​​​​​​​​​​​​​

With this jQuery

// click handler
function onClick(event) {
  var titles = $('input[name^=titles]').map(function(idx, elem) {
    return $(elem).val();
  }).get();

  console.log(titles);
  event.preventDefault();
}

// attach button click listener on dom ready
$(function() {
  $('button').click(onClick);
});

See it working here on jsFiddle

EDIT

This answer gives you the titles in an array instead of a string using a | separator. Personally, I think this is a lot more usable.

If you're just submitting the form and you want to support multiple values, use the .serialize method as described in the other answer