Tumblr Reply On Blog Page

<div class="reply-form">
    <form id="form-{PostID}" method="POST" name="form-{PostID}" action="http://www.tumblr.com/reply">
        <textarea name="reply_text" maxlength="250" title="250 max"></textarea>
        <input type="hidden" name="post_id" value="{PostID}">
        <input type="hidden" name="key" value="">
        <button type="submit">Reply</button>
    </form>
</div>
<script type="text/javascript">
    var notes = '{PostNotesURL}';
    var form = document.forms["form-{PostID}"];
    form.getElementsByTagName('input')[1].value = notes.substr(notes.lastIndexOf('/') + 1);
    $("#form-{PostID} button").on("click", function(e){
        e.preventDefault();
        $.ajax({
            type: 'POST',
            url: 'http://www.tumblr.com/reply',
            data: {
                "reply_text": form.getElementsByTagName('textarea')[0].value,
                "post_id": form.getElementsByTagName('input')[0].value,
                "key": form.getElementsByTagName('input')[1].value
            },
            dataType: "jsonp",
            crossDomain: true,
            jsonp: false,
            jsonpCallback: function() {
                form.parentNode.style.display = "none";
            }
        });
        return false;
    });
</script>