django template forloop.counter question

i have many fields in my form i was trying to apply different css to neighbour forms fields like

<li class='thiscolor' >
   <field>
</li>

<li class='thatcolor' >
   <field>
</li>

if there a way like

{% for field in form %}
    **{% if forloop.counter%2 == 0 %}**
   <li class='thiscolor'>
    {% else%}
   <li class='thatcolor'>     
    {%endif}
     {{field}}
    </li>
{% endfor %}

for forloop.counter ?

Thanks a lot!