jQuery Simple Example

HTML

<script src="//www.addressfinder.co.nz/assets/v2/widget.js"></script>
<div class="wrapper">
  <div class="col"></div>
  <div class="col"></div>
  <div class="col"></div>
</div>

SCSS

.wrapper {
  display: flex;
  flex-direction: row;
  justify-content: space-between;
  
  .col {
    width: 200px;
    height: 200px;
    background-color: gold;
    
    &.change-color {
      background-color: #000;
    }
  }
}

JavaScript

$(document).ready(function() {
  $('.col').on('click', function() {
  	$(this).addClass('change-color');
  });
});