SO - 15157403

by Arun P Johny

HTML

<span id="priceToSwap3">$238</span>

<select id="trapsize">
 <option data-price="238">item1</option>
 <option data-price="288">item2</option>
</select>

<select id="trapfabric">
 <option data-price="0">item3</option>
 <option data-price="20">item4</option>
</select>

JavaScript

$('#trapfabric, #trapsize').on('change', function() {
    var sum = $('#trapsize option:selected').data('price') + $('#trapfabric option:selected').data('price');
    $('#priceToSwap3').html('$' + sum);
});