Popover

<a href="#" class="btn btn-primary btn-small changeButton"
        rel="popover" data-placement="bottom"
        data-html="true"
        data-content="
        <form action='/start/' method='post'>{% csrf_token %}
    <fieldset>
        <legend>Date Selection</legend>
        <label>date:
            <input type='text' id='datepicker' name='date' placeholder='date of view'>
        </label>
        <button type='submit' class='btn btn-primary btn-small' value='submit'>Submit</button>
    </fieldset>
    </form>"
        >
    Change</a>


ajax

loading page
loading animation
http://jsfiddle.net/VpDUG/1844/