Here is my code:

2.  $(".form").submit(function(e) {
3.       e.preventDefault(); // avoid to execute the actual submit of the form.
4.       var url = $(this).attr("action"); // the script where you handle the form input.
5.       $.ajax({
6.              type: "POST",
7.              url: url,
8.              data: $("#form").serialize(), // serializes the form's elements.
9.              success: function(data)
10.              {
11.                 // var obj = jQuery.parseJSON( data );
12.                  alert(data); // show response from the php script.
13.              }
14.       });
15.   });

And, here my HTML code:

2. <form class="form" id="form" action="http://localhost:8888/api/addPost.php" method="POST">
3.     <div class="list">
4.  <label class="item item-input">
5.    <input type="text" placeholder="Title" class="AddPosttitle" name="title">
6.  </label>
7.  <label class="item item-input">
8.    <input class="description" type="text" placeholder="Simple Description (max 60 caracters)" maxlength="60" name="description">
9.  </label>
10.  <label class="item item-input">
11.    <div>
12.     <span id='button_upload'>Image : </span>
13.    <input type='file' class="img" name="img">
14. </div>
15.  </label>
16.  <label class="item item-input">
17.    <textarea placeholder="Full description" class="full" name="full"></textarea>
18.  </label>
19.   <div class="padding">
20.  <button class="button button-block button-positive submit-btn" type="submit">
21.       Submit
22.    </button>
23.     </div>
24. </div>
25. </form>

Basicaly, it returns me the text, but not the file, and I don't want to do 2 ajax requests