​x
 
<!DOCTYPE html>
<html>
<body>
​
<select id="mySelect">
</select>
​
<p>单击该按钮可创建一个 OPTION 元素。</p>
​
<button onclick="myFunction()">试一试</button>
​
<p id="demo"></p>
​
<script>
function myFunction() {
  var x = document.createElement("OPTION");
  x.setAttribute("value", "volvocar");
  var t = document.createTextNode("Volvo");
  x.appendChild(t);
  document.getElementById("mySelect").appendChild(x);
}
</script>
​
</body>
</html>
​