I will need to update the option values after a selection in Django template?

For example,

<select id="state" type="text" name="state" onChange="update()">
   <option value="">Select state</option>
   {% for state in state %}
   <option value="{{state.id}}"
       {{state.name|capfirst}}
   </option>
   {% endfor %}
</select>

After selection of the state I want to update the city queryset according to the selected state. For example, if anyone select California as their state, I want to just give the options of the cities that are inside California state.

<select id="city" type="text" name="city">
   <option value="">Select city</option>
   {% for city in city %}
   <option value="{{city.id}}"
       {{city.name|capfirst}}
   </option>
   {% endfor %}
</select>

Can anyone suggest what would be the best way to approach this?