问当下拉列表中的项目发生变化时，突出显示标签的简洁方法？

EN

$("#first_dd").change(function(){
   $("#first_lb").css('color',"yellow");
});

$('select').each(function(){         //for each select elements in document
    $(this).on('change',function(){  //bind change event
        var id = $(this).attr('id').replace('dd','lb'); //get id for label
        $("#"+id).css("color","yellow"); //highlight
    })
})

<select id="first_dd" data-bind="value: first">
    <option>cat</option>
    <option>dog</option>
    <option>squirrel</option>
    <option>birds</option>
</select>
<label for="first_dd">soft</label>

$('select').each(function(){
    $(this).on('change',function(){
        $('label[for="'+$(this).attr('id')+'"]').addClass('changed')
    })
})

.changed {
   color: #000;
}