W3Schools Tryit Editor

<!DOCTYPE html>
<html>
<head>
<style>
  #frameDiv {
    width: 200px;
    height: 200px;
    margin: 20px;
    position: relative;
    border: solid black 1px;
    background-color: rgb(205, 242, 205);
  }

#pinkDiv {
    width: 30px;
    height: 10px;
    border-radius: 3px 10px 10px 3px;
    background-color: hotpink;
    offset-path: path('M 75,100 C 75,150 150,150 150,100 M 150,100 C 150,50 75,50 75,100');
    animation: moveDiv linear 3s infinite;
  }

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

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

<p>The pink div is animated to follow a path written in SVG syntax.</p>

<p>Click the "Try it" button to change the path:</p>

<p>For more information on how to draw an SVG path visit <a href="https://www.w3schools.com/graphics/svg_path.asp" target="_blank">SVG Tutorial -> SVG Path</a></p>

</body>
</html>

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<!DOCTYPE html><html><head><style>  #frameDiv {    width: 200px;    height: 200px;    margin: 20px;    position: relative;    border: solid black 1px;    background-color: rgb(205, 242, 205);  }​  #pinkDiv {    width: 30px;    height: 10px;    border-radius: 3px 10px 10px 3px;    background-color: hotpink;    offset-path: path('M 75,100 C 75,150 150,150 150,100 M 150,100 C 150,50 75,50 75,100');    animation: moveDiv linear 3s infinite;  }​  @keyframes moveDiv {    100%  { offset-distance: 100%; }  }</style></head><body>​<h1>Change the offset-path property value with JavaScript</h1>​<p>The pink div is animated to follow a path written in SVG syntax.</p>​<p>Click the "Try it" button to change the path:</p>​<button onclick="myFunction()">Try it</button>​<div id="frameDiv">  <div id="pinkDiv"></div></div>​<p>For more information on how to draw an SVG path visit <a href="https://www.w3schools.com/graphics/svg_path.asp" target="_blank">SVG Tutorial -> SVG Path</a></p>​<script>  function myFunction() {    document.getElementById("pinkDiv").style.offsetPath = "path('M20,170 L100,20 L180,100 Z')";