Example of creating a glitchy effect using a linear-gradient:

Source Code: (back to article)

<!DOCTYPE html>
<html>
  <head>
    <title>The title of the document</title>
    <style>
      body,
      h1 {
        padding: 0;
        margin: 0;
        font-family: 'Montserrat', sans-serif;
      }
      #example {
        height: 100vh;
        width: 100%;
        margin: 0;
        padding: 0;
        display: flex;
        flex-direction: column;
        justify-content: center;
        align-items: center;
        background: linear-gradient(rgba(5, 5, 5, 0.6), rgba(0, 0, 0, 0)), repeating-linear-gradient(0, transparent, transparent 2px, black 3px, black 3px), url("https://images.unsplash.com/photo-1528372444006-1bfc81acab02?ixlib=rb-1.2.1&ixid=eyJhcHBfaWQiOjEyMDd9&auto=format&fit=crop&w=675&q=80");
        background-size: cover;
        background-position: center;
        z-index: 1;
      }
      #wrapper {
        text-align: center;
      }
      .glitch {
        position: relative;
        color: white;
        font-size: 4em;
        letter-spacing: .4em;
        animation: glitch-skew 0.5s infinite linear alternate-reverse;
      }
      .glitch::after {
        content: attr(data-text);
        position: absolute;
        top: 0;
        left: 0;
        width: 100%;
        height: 100%;
        left: -2px;
        text-shadow: -2px 0 #00fff9, 2px 2px #ff00c1;
        animation: glitch-anim2 1s infinite linear alternate-reverse;
      }
      @keyframes glitch-anim {
        0% {
          clip: rect(30px, 9999px, 42px, 0);
          transform: skew(0.85deg);
        }
        5% {
          clip: rect(59px, 9999px, 21px, 0);
          transform: skew(0.34deg);
        }
        10% {
          clip: rect(99px, 9999px, 15px, 0);
          transform: skew(0.01deg);
        }
        15% {
          clip: rect(25px, 9999px, 61px, 0);
          transform: skew(0.97deg);
        }
        20% {
          clip: rect(35px, 9999px, 42px, 0);
          transform: skew(0.94deg);
        }
        25% {
          clip: rect(39px, 9999px, 62px, 0);
          transform: skew(0.31deg);
        }
        30% {
          clip: rect(62px, 9999px, 55px, 0);
          transform: skew(0.9deg);
        }
        35% {
          clip: rect(36px, 9999px, 31px, 0);
          transform: skew(0.13deg);
        }
        40% {
          clip: rect(27px, 9999px, 26px, 0);
          transform: skew(0.01deg);
        }
        45% {
          clip: rect(55px, 9999px, 9px, 0);
          transform: skew(0.5deg);
        }
        50% {
          clip: rect(69px, 9999px, 73px, 0);
          transform: skew(0.85deg);
        }
        55% {
          clip: rect(53px, 9999px, 89px, 0);
          transform: skew(0.15deg);
        }
        60% {
          clip: rect(20px, 9999px, 28px, 0);
          transform: skew(0.62deg);
        }
        65% {
          clip: rect(81px, 9999px, 28px, 0);
          transform: skew(0.1deg);
        }
        70% {
          clip: rect(54px, 9999px, 93px, 0);
          transform: skew(0.3deg);
        }
        75% {
          clip: rect(22px, 9999px, 6px, 0);
          transform: skew(0.84deg);
        }
        80% {
          clip: rect(23px, 9999px, 5px, 0);
          transform: skew(0.55deg);
        }
        85% {
          clip: rect(24px, 9999px, 76px, 0);
          transform: skew(0.68deg);
        }
        90% {
          clip: rect(3px, 9999px, 29px, 0);
          transform: skew(0.48deg);
        }
        95% {
          clip: rect(43px, 9999px, 95px, 0);
          transform: skew(0.37deg);
        }
        100% {
          clip: rect(58px, 9999px, 66px, 0);
          transform: skew(0.05deg);
        }
      }
      @keyframes glitch-anim2 {
        0% {
          clip: rect(66px, 9999px, 28px, 0);
          transform: skew(0.12deg);
        }
        5% {
          clip: rect(85px, 9999px, 40px, 0);
          transform: skew(0.7deg);
        }
        10% {
          clip: rect(14px, 9999px, 33px, 0);
          transform: skew(0.81deg);
        }
        15% {
          clip: rect(48px, 9999px, 76px, 0);
          transform: skew(0.57deg);
        }
        20% {
          clip: rect(77px, 9999px, 16px, 0);
          transform: skew(0.4deg);
        }
        25% {
          clip: rect(15px, 9999px, 43px, 0);
          transform: skew(0.27deg);
        }
        30% {
          clip: rect(33px, 9999px, 11px, 0);
          transform: skew(0.84deg);
        }
        35% {
          clip: rect(50px, 9999px, 51px, 0);
          transform: skew(0.16deg);
        }
        40% {
          clip: rect(52px, 9999px, 11px, 0);
          transform: skew(0.21deg);
        }
        45% {
          clip: rect(39px, 9999px, 58px, 0);
          transform: skew(0.98deg);
        }
        50% {
          clip: rect(88px, 9999px, 42px, 0);
          transform: skew(0.42deg);
        }
        55% {
          clip: rect(98px, 9999px, 11px, 0);
          transform: skew(0.51deg);
        }
        60% {
          clip: rect(73px, 9999px, 73px, 0);
          transform: skew(0.81deg);
        }
        65% {
          clip: rect(82px, 9999px, 59px, 0);
          transform: skew(1deg);
        }
        70% {
          clip: rect(64px, 9999px, 84px, 0);
          transform: skew(0.94deg);
        }
        75% {
          clip: rect(41px, 9999px, 44px, 0);
          transform: skew(0.38deg);
        }
        80% {
          clip: rect(23px, 9999px, 35px, 0);
          transform: skew(0.54deg);
        }
        85% {
          clip: rect(20px, 9999px, 100px, 0);
          transform: skew(0.76deg);
        }
        90% {
          clip: rect(9px, 9999px, 96px, 0);
          transform: skew(0.64deg);
        }
        95% {
          clip: rect(29px, 9999px, 82px, 0);
          transform: skew(0.47deg);
        }
        100% {
          clip: rect(15px, 9999px, 94px, 0);
          transform: skew(0.76deg);
        }
      }
      @keyframes glitch-skew {
        0% {
          transform: skew(2deg);
        }
        10% {
          transform: skew(4deg);
        }
        20% {
          transform: skew(4deg);
        }
        30% {
          transform: skew(-2deg);
        }
        40% {
          transform: skew(4deg);
        }
        50% {
          transform: skew(2deg);
        }
        60% {
          transform: skew(-3deg);
        }
        70% {
          transform: skew(-1deg);
        }
        80% {
          transform: skew(-3deg);
        }
        90% {
          transform: skew(-2deg);
        }
        100% {
          transform: skew(-2deg);
        }
      }
    </style>
  </head>
  <body>
    <div id="example">
      <div id="wrapper">
        <h1 class="glitch" data-text="glitch">glitch</h1>
      </div>
    </div>
  </body>
</html>