jQuery addClass example

Change class name on click in jQuery

by John Pisello

HTML

<div id="banner-message">
  <h2>
  Banner title
  </h2>
  <p>Banner message goes here. Yes, it goes here. Totally here. Not there, but here.</p>
  <button>Change color</button>
  <a class="expando" title="expand banner"></a>
</div>

CSS

body {
  background: #20262E;
  padding: 2rem;
  font-family: Helvetica;
}

#banner-message {
  background: #fff;
  border-radius: 4px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  padding: 2rem;
  /* font-size: 25px; */
  position: relative;
  /* text-align: center; */
  transition: all 0.5s ease-in-out;
  margin: 0 auto;
  width: 20rem;
  height: auto;
  min-height: 6rem;
  will-change: width height;
}
#banner-message > h2,
#banner-message > button ,
#banner-message > p {
  flex: 0 0 auto;
  margin: 0 0 1rem;
  /* padding: 0; */
}
#banner-message > p {
  flex-grow: 1; 
}

#banner-message .expando {
  background-color: #0084ff;
  background-image: radial-gradient(ellipse at center, rgba(255, 255, 255, 0) 0%, rgba(255, 255, 255, 0) 50%, rgba(255, 255, 255, 1) 51%, rgba(255, 255, 255, 1) 100%);
  background-size: .5rem .5rem;
  border-radius: .25rem;
  content: '';
  cursor: zoom-in;
  width: 1.5rem;
  height: 1.5rem;
  position: absolute;
  bottom: .125rem;
  right: .125rem;
  transform: rotate3d(1, -1, 0, 0);
  transform-style: preserve-3d;
  transition: transform 1.5s ease-in-out;
}
#banner-message .expando::before {
  background-color: white;
  border-radius: .25rem;
  content: '';
  width: 1rem;
  height: .5rem;
  position: absolute;
  top: 0;
  left: 0;
  z-index: 10;
}
#banner-message .expando::after {
  background-color: white;
  border-radius: .25rem;
  content: '';
  width: .5rem;
  height: 1rem;
  position: absolute;
  top: 0;
  left: 0;
  z-index: 10;
}

#banner-message.expanded {
  width: 600px;
  height: 200px;
}

#banner-message.expanded .expando {
  cursor: zoom-out;
  transform: rotate3d(1, -1, 0, -180deg);
}

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")
var expando = $(".expando")

// handle click and add class
button.on("click", function(){
  banner.addClass("alt")
})
expando.on("click", function() {
	$(this.parentElement).toggleClass('expanded');
})