如何清除“textfield”

document.getElementById("textfield").value = "";

<input type="text" id="textfield">
<button onclick="clearText()">清除</button>

<script>
function clearText() {
  document.getElementById("textfield").value = "";
}
</script>

<input type="text" id="textfield" class="clearable">

.clearable {
  background-image: url('clear-icon.png');
  background-position: right center;
  background-repeat: no-repeat;
  padding-right: 20px;
}

.clearable::-ms-clear {
  display: none;
}

.clearable::-webkit-clear-button {
  display: none;
}