JSFiddle - React, Tailwind, and code Playground

HTML

<ul>
<li>
      <p>iMac 27&quot;</p>
      <input class="total" value="$0" id="total_item_28" name="total_item_28" disabled="disabled" />
      <input class="rate" value="$220" id="price_item_28" name="price_item_28" disabled="disabled" />
      <input class="qty" placeholder="0" id="qty_item_28" name="qty_item_28" />
      <a href="#" class="orderBtn"><span>add to order</span></a></li>
    <li>
      <p>LCD/Plasma Wall Bracket </p>
      <input class="total" value="$0" id="total_item_29" name="total_item_29" disabled="disabled" />
      <input class="rate" value="$220" id="price_item_29" name="price_item_29" disabled="disabled" />
      <input class="qty" placeholder="0" id="qty_item_29" name="qty_item_29" />
      <a href="#" class="orderBtn"><span>add to order</span></a></li>
    <li>
      <p>2 Mbps Wireless Internet Access inc Router </p>
      <input class="total" value="$0" id="total_item_30" name="total_item_30" disabled="disabled" />
      <input class="rate" value="$220" id="price_item_30" name="price_item_30" disabled="disabled" />
      <input class="qty" placeholder="0" id="qty_item_30" name="qty_item_30" />
      <a href="#" class="orderBtn"><span>add to order</span></a></li>
</ul>

<select size="4" multiple="multiple">
    <option>Pick Me</option>
</select>

JavaScript

$('.orderBtn').click(function() {
    var $index = $(this).closest('li').index();
    if ($('select option#' + $index).length) {
        $('select option#' + $index).remove();
    } else {
        $('select').append( '<option id=' + $index + '>'+$(this).closest('li').find('input.qty').val() +'x '+$(this).closest('li').find('p').text() +'</option>' );
    }
    
});