jQuery addClass example

Change class name on click in jQuery

HTML

<picture >
  <source media="(min-width: 992px)" srcset="https://www.lesfurets.com/static/8e8c5af1/responsive-2018/dist/images/desktop-bg-top-layer-home.jpg">
  <source media="(min-width: 576px)" srcset="https://www.lesfurets.com/static/8e8c5af1/responsive-2018/dist/images/tablet-bg-top-layer-home.jpg">
  <source srcset="https://www.lesfurets.com/static/8e8c5af1/responsive-2018/dist/images/mobile-bg-top-layer-home.jpg">
  <img src="https://www.lesfurets.com/static/8e8c5af1/responsive-2018/dist/images/desktop-bg-top-layer-home.jpg">
</picture>

CSS

body {
  background: #20262E;
  padding: 20px;
  font-family: Helvetica;
}

#banner-message {
  background: #fff;
  border-radius: 4px;
  padding: 20px;
  font-size: 25px;
  text-align: center;
  transition: all 0.2s;
  margin: 0 auto;
  width: 300px;
}

button {
  background: #0084ff;
  border: none;
  border-radius: 5px;
  padding: 8px 14px;
  font-size: 15px;
  color: #fff;
}

#banner-message.alt {
  background: #0084ff;
  color: #fff;
  margin-top: 40px;
  width: 200px;
}

#banner-message.alt button {
  background: #fff;
  color: #000;
}

JavaScript

// find elements
var banner = $("#banner-message")
var button = $("button")

// handle click and add class
button.on("click", function(){
  banner.addClass("alt")
})