【select】
<!DOCTYPE html>
<html>
<head>
<script type='text/javascript'>
window.onload=function(){
var selectElement = document.body.firstElementChild;
selectElement.value = "jp";
}
</script>
</head>
<body>
<select name="country">
<option value="us">America</option>
<option value="jp">Japan</option>
<option value="cn">China</option>
<option value="vi">Vietnam</option>
</select>
</body>
</html>
