I am trying to assign a click event to span elements with class 'open' and 'appoint'. But I cannot get it to work. Code is as shown below.

HTML:

```
            <td><span id = "28" class='open'>28</span></td>
            <td><span id = "29" class='open'>29</span></td>
            <td><span id = "30" class='closed'>30</span></td>
            <td><span id = "31" class='appoint'>31</span></td>
            <td><span id = "32" class='closed'>32</span></td>

```

JS:

```
            $("span[class='open'][class='appoint']").click(function() {

                alert($(this).html());

            });

```

I have tried below combinations too, but nothing seems to work.

```
$("span.open.appoint")
$("span .open .appoint")
$("span .open, .appoint")

```