JavaScript - Validar clic en combobox

<select id="id_Departamento" name="selected" class="form-control" required="required">

	<option value="0">------------</option>

	{% for departamento in departamentos %}

	<option multiple="selected" multiple="multiple" value="{{departamento.id}}">{{departamento.nombre}}</option>

	{% endfor %}

</select>

<select id="id_Municipio" name="selected" class="form-control" required="required" >

	<option value="0">------------</option>

	{% for municipio in municipios %}

	<option multiple="multiple" value="{{municipio.id}}">{{municipio.nombre}}</option>

	{% endfor %}

</select>

<select id="id_Aldea" name="selected" class="form-control" required="required" >

	<option value="0">------------</option>

	{% for aldea in aldeas %}

	<option multiple="multiple" value="{{aldea.id}}">{{aldea.nombre}}</option>

	{% endfor %}

</select>

<button id="ver">Ver</button>