<form>

    another text input<input type="text"><br>

    add title<input type="text" id="addTitle"><br>

    another text input<input type="text"><br>

    <input type="button" value="button"><br>

    <input type="submit" value="submit"><br>

  </form>

<script src="https://code.jquery.com/jquery-3.1.0.js"></script>

<Script>

  $(function(){

  $("#addTitle").on('keyup', function(e){

        var keyCode = e.keyCode || e.which;

        if (keyCode == 13){

            console.log("ENTER PRESSED on input text");

        }

    });

  $('form').submit(function(e){

    e.preventDefault();

    if($(this).find('#addTitle').is(':focus') === false){

      doAjaxForm();

    }

  });

  $('input[type="submit"]').click(function(){

    doAjaxForm();

  });

  function doAjaxForm(){

    console.log('do ajax form');

  }  

})

  </script>