问Ajax表单提交问题

EN

<form id="post_edit">
<input type="hidden" id="id" name="id" value="1">
<input type="text" id="title" name"title" value="This is the title">
<textarea id="body" name="body" rows="3">This is the body</textarea>
<button type="submit" onclick="this.form.submit();" data-dismiss="modal">Save</button>

$("#post_edit").submit(function(e) {

            e.preventDefault(); 

            var form = $(this);
            var url = 'http://localhost/ajax/posts/' + form.attr('id');

            $.ajax({
                type: "PATCH",
                url: url,
                data: form.serialize(), // serializes the form's elements.
                success: function(data)
                {
                    toastr.success('The post was successfully updated!')
                },
                error:function() {
                    toastr.error('Unable to save changes to the post.<br />Please try again later.')
                }
            });

        });