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HTML

CSS

CSS Base

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HTML

              
                <!-- This version uses pseudo element, so it does not work on IE9 and Android stock browsers prior to Kitkat. For a version which support those browsers, please check out https://codepen.io/thith/pen/vEOObL -->

<!-- For explanation, visit http://www.mangcut.vn/blog/2014-11-26-sonar-effect-with-css.html -->

<div class="sonar-wrapper">
	<div class="sonar-emitter"></div>
</div>
              
            
!

CSS

              
                /* Make it looks good on CodePen */
html {
  background-color: skyblue;
}
html, body, .sonar-wrapper {
  height: 100%;
}

/* Prevent scrollbars to appear when waves go out of bound */
.sonar-wrapper {
  overflow: hidden;
}

/* The circle */
.sonar-emitter {
  position: relative;
  margin: 32px auto;
  width: 160px;
  height: 160px;
  border-radius: 50%;
  background-color: red;
  z-index: 0;
}

/* pseudo element - same shape and size as its parent */
.sonar-emitter::after {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  border-radius: 50%;
  content: '';
  background-color: red;
  z-index: -1;
  pointer-events: none;
  opacity: 0;
}

/*
  Animate the pseudo element.
  NOTE: add browser prefixes where needed.
*/
.sonar-emitter::after {
  animation: sonarWave 2s linear infinite;
}

@keyframes sonarWave {
  from {
    opacity: 0.5;
  }
  to {
    transform: scale(2.5);
    opacity: 0;
  }
}

              
            
!

JS

              
                
              
            
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999px

Console