本文实例讲述了JS实现的简单下拉框联动功能。分享给大家供大家参考，具体如下：
<!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>www.qb5200.com JS下拉联动</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>
使用在线HTML/JS/css运行工具http://tools.softyun.net/code/HtmlJsRun，简单效果图如下：
使用innerHTML，IE浏览器不支持这种方法的，所以改进方法：
<!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>www.qb5200.com JS下拉联动</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");//可设置循环配置，也可一个一个配置
}
}
</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
希望本文所述对大家JavaScript程序设计有所帮助。
