很简单的js下拉框联动

</p><p>使用innerHTML，IE浏览器不支持这种方法的，所以改进方法：</p><p><br></p><p></p><textarea readonly name="code" class="html">&lt;!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"&gt;&lt;html xmlns="http://www.w3.org/1999/xhtml"&gt;&lt;head&gt;&lt;meta http-equiv="Content-Type" content="text/html; charset=utf-8" /&gt;&lt;title&gt;Untitled Document&lt;/title&gt;&lt;script&gt;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}}&lt;/script&gt;&lt;/head&gt;&lt;body&gt;&lt;div&gt; &lt;select id="first" onchange="setSecond(this)"&gt; &lt;option value="en"&gt;en&lt;/option&gt; &lt;option value="zh"&gt;zh&lt;/option&gt; &lt;/select&gt; &lt;/div&gt;&lt;div&gt; &lt;select id="second"&gt; &lt;/select&gt; &lt;/div&gt;&lt;/body&gt;&lt;/html&gt;
可以兼容火狐，IE等