I have 3 values in the select: rock, paper, scissor.

The first time I choose a value in the select (rock, paper or scissor), the onChange event fires, and the @keyframes animation works for all 3 values.

But the second time I choose any of the values, the animation no longer works.
I do not understand why.

The code is this:
[jsfiddle.net/9efvxph3/83/](http://jsfiddle.net/9efvxph3/83/)

```css
body {
  background: radial-gradient(gold, goldenrod);
  font-family: monospace;
  text-align: center;
  font-size: 1.5rem;
}

@keyframes example {
  0% {
    transform: scale(1);
  }

  100% {
    transform: scale(1.3);
  }
}

img {
  padding: 10px;
  height: 100px;
  width: auto;
}

img:hover {
  transform: scale(1.4);
  transition: all 1s;
}
```

```html
          <select id="choice" onchange="winner()">
            <option value="" disabled selected>choose</option>
            <option value="rock">rock</option>
            <option value="paper">paper</option>
            <option value="scissors">scissors</option>
          </select>

          <img src="https://img.icons8.com/windows/2x/hand-rock.png" class="user-choice">
          <img src="https://img.icons8.com/wired/2x/paper.png" class="user-choice">
          <img src="https://img.icons8.com/ios/2x/hand-scissors.png" class="user-choice">

          <h3 id="result"> </h3>

          <script>
            const type = ["paper", "scissors", "rock"];

            function winner() {
              var index = document.getElementById("choice").selectedIndex;

              var userChooice = document.getElementById("choice").value;
              var PcChooice = type[Math.floor(Math.random() * type.length)];

              document.getElementsByClassName("user-choice").item(index - 1).style = "animation:example 0.5s alternate";

              if (PcChooice == userChooice) {

                document.getElementById("result").innerHTML = userChooice + " - " + PcChooice + ": You tied";

              } else {
                if ((userChooice == "rock") && (PcChooice == "scissors")) {
                  document.getElementById("result").innerHTML = userChooice + " - " + PcChooice + ": You win";
                } else if ((userChooice == "paper") && (PcChooice == "rock")) {
                  document.getElementById("result").innerHTML = userChooice + " - " + PcChooice + ": You win";
                } else if ((userChooice == "scissors") && (PcChooice == "paper")) {
                  document.getElementById("result").innerHTML = userChooice + " - " + PcChooice + ": You win";
                } else {
                  document.getElementById("result").innerHTML = userChooice + " - " + PcChooice + ": You loose";
                }
              }
              document.getElementById("choice").selectedIndex = 0;
            };

          </script>
```