<select name="selector[]" id="selector">
   <option value="1">Valor 1</option>
   <option value="2">Valor 2</option>
</select>

<select name="selector[]" id="selector">
   <option value="1">Valor 1</option>
   <option value="2">Valor 2</option>
</select>

$('#selector').on('change', function(e){
     e.preventDefault();
     // acciones
});