jQuery obter valor de option clicada
HTML
<p>Valor: <span></span></p>
<select id="multiselect" multiple="multiple">
<option value="pedra">Pedra</option>
<option value="papel">Papel</option>
<option value="tesoura">Tesoura</option>
</select>JavaScript
$('#multiselect').on("click", 'option', function() {
$('p span').html($(this).val());
});