jQuery addClass example

Change class name on click in jQuery

HTML

<div class="banner-message">
Hello 1
</div>
<div class="banner-message">
Hello 2
</div>
<div class="banner-message">
Hello 3
</div>
<button>Click</button>
Количество: <span class="counter"></span>

CSS

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

.hide {
  display: none;
}

.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

$("div").on("DOMAttrModified", function(){
  $('.counter').text($(".banner-message:visible").length);
})

$("button").on("click", function(){
	$(".banner-message:first").toggleClass("hide")
})