CSS motion path onClick

Question

I need help with my CSS and javascript code which I have uploaded to codepen.

I am trying to use CSS motion path, I would like to be able to control this with JavaScript, so when you press the "Forward button" it runs to the last keyframe and that works, But when I press the "Back button" then nothing happens. I will like it to move back to the first keyframe.

The question if I am on the right track with my code? and what I need to change?

function myForwardFunction() {
  document.getElementById("pathed").style.animationPlayState = "running";
}

function myBackFunction() {
  document.getElementById("pathed").style.animationDirection = "reverse";
}

section {
  width: 244px;
  height: 200px;
  border: 2px dashed lightgrey;
}

body {
  display: flex;
  padding: 10px;
  flex-wrap: wrap;
  gap: 30px;
  margin: 0;
  height: 100vh;
  justify-content: center;
  align-items: center;
}

div {
  width: 50px;
  height: 50px;
  border: 1px solid hsl(343, 100%, 58%, .3);
  border-right: 5px solid hsl(343, 100%, 58%);
  background: hsla(343, 100%, 58%, .3) radial-gradient(circle, hsl(343, 100%, 58%, 1) 3px, hsl(343, 100%, 58%, 0) 3px);
  display: flex;
  justify-content: center;
  align-items: center;
  font-family: monospace, sans-serif;
}

.pathed {
  offset-path: path('M0,0 C40,240 200,240 240,0');
  position: absolute;
  animation: distance 4000ms alternate ease-in-out;
  animation-play-state: paused;
  animation-fill-mode: both;
  animation-direction: normal;
}

@keyframes distance {
  from {
    offset-distance: 0%;
  }
  to {
    offset-distance: 100%;
  }
}

code {
  position: absolute;
  top: 100px;
  right: 10px;
  left: 10px;
  line-height: 1.5;
}

section {
  position: relative;
}

* {
  box-sizing: border-box;
}

svg {
  position: absolute;
  opacity: .333;
  stroke-width: 2px;
}

<button onclick="myForwardFunction()">Forward</button>

<button onclick="myBackFunction()">Back</button>


<section>
  <svg viewBox="0 0 240 200"><path d="M0,0 C40,240 200,240 240,0" fill="none" stroke="lightgrey"/></svg>
  <div id="pathed" class="pathed"></div>
</section>

Answer 1

You may also toggle a class and use a transition:

function myForwardFunction() {
  document.getElementById("pathed").classList.add('to100');
}
function myBackFunction() {
  document.getElementById("pathed").classList.toggle('to100');
}

section {
  width: 244px;
  height: 200px;
  border: 2px dashed lightgrey;
}

body {
  display: flex;
  padding: 10px;
  flex-wrap: wrap;
  gap: 30px;
  margin: 0;
  height: 100vh;
  justify-content: center;
  align-items: center;
}

div {
  width: 50px;
  height: 50px;
  border: 1px solid hsl(343, 100%, 58%, .3);
  border-right: 5px solid hsl(343, 100%, 58%);
  background: hsla(343, 100%, 58%, .3) radial-gradient(circle, hsl(343, 100%, 58%, 1) 3px, hsl(343, 100%, 58%, 0) 3px);
  display: flex;
  justify-content: center;
  align-items: center;
  font-family: monospace, sans-serif;
}

.pathed {
  offset-path: path('M0,0 C40,240 200,240 240,0');
  position: absolute;
  transition: 4s;
  offset-distance: 0%;
}

.pathed.to100 {
  offset-distance: 100%;
}

code {
  position: absolute;
  top: 100px;
  right: 10px;
  left: 10px;
  line-height: 1.5;
}

section {
  position: relative;
}

* {
  box-sizing: border-box;
}

svg {
  position: absolute;
  opacity: .333;
  stroke-width: 2px;
}
small {font-size:0.6em}

<button onclick="myForwardFunction()">Forward</button>
<button onclick="myBackFunction()">Back<small>/toggle direction</small></button>


<section>
  <svg viewBox="0 0 240 200"><path d="M0,0 C40,240 200,240 240,0" fill="none" stroke="lightgrey"/></svg>
  <div id="pathed" class="pathed"></div>
</section>

edit as suggested by @wizzwizz4 comment , you can use your js to set the onclick function on your button:

let btn = document.querySelector('#click');
let div = document.querySelector('#pathed');
btn.addEventListener("click", function() {
  this.classList.toggle('to100');
  div.classList.toggle('to100');
});

section {
  width: 244px;
  height: 200px;
  border: 2px dashed lightgrey;
}

body {
  display: flex;
  padding: 10px;
  flex-wrap: wrap;
  gap: 30px;
  margin: 0;
  height: 100vh;
  justify-content: center;
  align-items: center;
}

div {
  width: 50px;
  height: 50px;
  border: 1px solid hsl(343, 100%, 58%, .3);
  border-right: 5px solid hsl(343, 100%, 58%);
  background: hsla(343, 100%, 58%, .3) radial-gradient(circle, hsl(343, 100%, 58%, 1) 3px, hsl(343, 100%, 58%, 0) 3px);
  display: flex;
  justify-content: center;
  align-items: center;
  font-family: monospace, sans-serif;
}

.pathed {
  offset-path: path('M0,0 C40,240 200,240 240,0');
  position: absolute;
  transition: 4s;
  offset-distance: 0%;
}

.pathed.to100 {
  offset-distance: 100%;
}

#click:after {
  content: ' forwards';
}

#click.to100:after {
  content: ' backwards';
}

code {
  position: absolute;
  top: 100px;
  right: 10px;
  left: 10px;
  line-height: 1.5;
}

section {
  position: relative;
}

* {
  box-sizing: border-box;
}

svg {
  position: absolute;
  opacity: .333;
  stroke-width: 2px;
}

small {
  font-size: 0.6em
}

<button id=click>Click to go</button>


<section>
  <svg viewBox="0 0 240 200"><path d="M0,0 C40,240 200,240 240,0" fill="none" stroke="lightgrey"/></svg>
  <div id="pathed" class="pathed"></div>
</section>