Create a Custom Snippet or Embed Code

Use the Website → Edit → HTML/Embed Code block to paste your custom tool’s HTML/JS.
Example:
​<div id="colorDisplay" style="width:100%;height:100vh;background:#ffffff;cursor:pointer;" onclick="toggleFullscreen(this)">

</div>

<div style="margin-top:20px;">

  <label>Pick a Color: </label>

  <input type="color" id="colorPicker" onchange="changeColor(this.value)">

  <label> or enter RGB: </label>

  <input type="text" id="rgbInput" placeholder="#FFFFFF" oninput="changeColor(this.value)">

</div>

<script>

function changeColor(color) {

  document.getElementById("colorDisplay").style.background = color;

}

function toggleFullscreen(elem) {

  if (!document.fullscreenElement) {

    elem.requestFullscreen().catch(err => alert(err.message));

  } else {

    document.exitFullscreen();

  }

}

</script>

i hope it is usefull