HTML-CSS: Pulse loader

Last update on May 28 2022 07:25:43 (UTC/GMT +8 hours)

HTML-CSS : Exercise-12 with Solution

Using HTML, CSS create a pulse effect loader animation using the animation-delay property.

Use @keyframes to define an animation at two points in the cycle. At the start (0%), the two <div> elements have no width or height and are positioned at the center. At the end (100%), both <div> elements have increased width and height, but their position is reset to 0.
Use opacity to transition from 1 to 0 when animating to give the <div> elements a disappearing effect as they expand.
Set a predefined width and height for the parent container, .ripple-loader and use position: relative to position its children.
Use animation-delay on the second <div> element, so that each element starts its animation at a different time.

HTML Code:

<!--License: https://bit.ly/3GjrtVF-->
<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width">
  <title>Using HTML, CSS create a pulse effect loader animation using the animation-delay property</title>
</head>
<body>
<strong>Preview:</strong><br>
<div class="ripple-loader">
  <div>w3r</div>
  <div>w3r</div>
</div>
</body>
</html>

CSS Code:

<style> 

.ripple-loader {
  position: relative;
  width: 64px;
  height: 64px;
}

.ripple-loader div {
  position: absolute;
  border: 4px solid #AA4A44;
  border-radius: 50%;
  animation: ripple-loader 1s ease-out infinite;
}

.ripple-loader div:nth-child(2) {
  animation-delay: -0.5s;
}

@keyframes ripple-loader {
  0% {
    top: 32px;
    left: 32px;
    width: 0;
    height: 0;
    opacity: 1;
  }
  100% {
    top: 0;
    left: 0;
    width: 64px;
    height: 64px;
    opacity: 0;
  }
}

</style>

HTML-CSS Editor:

See the Pen html-css-practical-exercises by w3resource (@w3resource) on CodePen.

HTML-CSS: Tips of the Day

What is the difference between id and class in CSS, and when should I use them?

Example:

#header_id {font-color:#fff} .header_class {font-color:#000}

(Note that CSS uses the prefix # for IDs and . for Classes.)

However color was an HTML 4.01 <font> tag attribute deprecated in HTML 5. In CSS there is no "font-color", the style is color so the above should read:

Example:

#header_id {color:#fff} .header_class {color:#000}

The text would be white.

Ref: https://bit.ly/39Stv4P