Tryit Editor v2.9

Edit This Code:
<!DOCTYPE html>
<html>
<body>

<form>
  What color do you prefer?<br>
  <input type="radio" name="colors" id="red">Red<br>
  <input type="radio" name="colors" id="blue">Blue
</form>

<button onclick="check()">Check "Red"</button>
<button onclick="uncheck()">Uncheck "Red"</button>

<script>
function check() {
    document.getElementById("red").checked = true;
}
function uncheck() {
    document.getElementById("red").checked = false;
}
</script>

</body>
</html>