W3Schools Tryit Editor

<!DOCTYPE html>
<html>
<head>
<style>
  #frameDiv {
    width: 300px;
    height: 300px;
    margin: 20px;
    position: relative;
    border: solid black 1px;
    background-color: rgb(205, 242, 205);
  }
  #circleDiv {
    border: solid darkred 3px;
    height: 10px;
    width: 10px;
    border-radius: 50%;
    position: absolute;
    z-index: 2;
    box-sizing: border-box;
    offset-path: path('M 50,150 C 50,275 250,275 250,150 M 250,150 C 250,25 50,25 50,150');
    animation: moveDiv linear 7s infinite;
  }

svg {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
  }

#pinkDiv {
    position: absolute;
    background-color: hotpink;
    opacity: 0.5;
    z-index: 1;
    width: 45px;
    height: 45px;
    offset-path: path('M 50,150 C 50,275 250,275 250,150 M 250,150 C 250,25 50,25 50,150');
    offset-rotate: 0deg;
    animation: moveDiv linear 7s infinite;
  }

@keyframes moveDiv {
    100%  { offset-distance: 100%; }
  }
</style>
</head>
<body>

<h1>Change the offset-anchor property value with JavaScript</h1>

<p>The pink box is achored to the path so that it is fastened to the path at its center. This is default.</p>

<p>Click the "Try it" button to change the achored point to the right bottom corner of the pink box:</p>

</body>
</html>