<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Untitled Document</title>
<script>
function setSecond(obj){
var val = obj.value;
if(val == 'en'){
var sec = document.getElementById('second');
sec.innerHTML = "<option>one</option><option>two</option>";
}else{
var sec = document.getElementById('second');
sec.innerHTML = "<option>一</option><option>二</option>";
}
}
</script>
</head>
<body>
<div>
<select id="first" onchange="setSecond(this)">
<option value="en">en</option>
<option value="zh">zh</option>
</select>
</div>
<div>
<select id="second">
</select>
</div>
</body>
</html>
簡單效果圖：
使用innerHTML，IE瀏覽器不支持這種方法的，所以改進方法：
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Untitled Document</title>
<script>
function setSecond(obj){
var val = obj.value;
if(val == 'en'){
var sec = document.getElementById('second');
sec.options[0] = new Option("one","one");
sec.options[1] = new Option("two","two");
}else{
var sec = document.getElementById('second');
sec.options[0] = new Option("一","one");
sec.options[1] = new Option("二","two");//可設置循環配置，也可一個一個配置
}
}
</script>
</head>
<body>
<div>
<select id="first" onchange="setSecond(this)">
<option value="en">en</option>
<option value="zh">zh</option>
</select>
</div>
<div>
<select id="second">
</select>
</div>
</body>
</html>
可以兼容火狐，IE等