js操作select（添加、移除、获取select值），很实用。
如图：
代码如下：
<html><html><TITLE>选择下拉菜单</TITLE><meta http-equiv="Content-Type" content="text/html; charset=gb2312"><META NAME="Description" CONTENT="Power by hill"></HEAD><body><p>选定一项或多项然后点击添加或移除(按住shift或ctrl可以多选)，或在选择项上双击进行添加和移除。</p><form method="post" name="myform"><table border="0" width="400"><tr><td width="40%"><select style="height:200px;WIDTH:300px" multiple name="list1" size="10" οndblclick="moveOption(document.myform.list1, document.myform.list2)"><!--用forEach遍历出所有的option--><option value="北京">北京</option><option value="上海">上海</option><option value="山东">山东</option><option value="安徽">安徽</option><option value="重庆">重庆</option><option value="福建">福建</option><option value="甘肃">甘肃</option><option value="广东">广东</option><option value="广西">广西</option><option value="贵州">贵州</option><option value="海南">海南</option><option value="河北">河北</option><option value="黑龙江">黑龙江</option></select></td><td width="20%" align="center"><input type="button" value="全部添加" οnclick="moveAllOption(document.myform.list1, document.myform.list2)"><br/><br/><input type="button" value="添加" οnclick="moveOption(document.myform.list1, document.myform.list2)"><br/><br/><input type="button" value="移除" οnclick="moveOption(document.myform.list2, document.myform.list1)"><br/><br/><input type="button" value="全部移除" οnclick="moveAllOption(document.myform.list2, document.myform.list1)"></td><td width="40%"><select style="height:200px;WIDTH:300px" multiple name="list2" size="12" οndblclick="moveOption(document.myform.list2, document.myform.list1)"></select></td></tr></table>值：<input type="text" name="city" size="40"></form><script language="JavaScript"><!--操作全部-->function moveAllOption(e1, e2){var fromObjOptions=e1.options;for(var i=0;i<fromObjOptions.length;i++){fromObjOptions[0].selected=true;e2.appendChild(fromObjOptions[i]);i--;}document.myform.city.value=getvalue(document.myform.list2);}<!--操作单个-->function moveOption(e1, e2){var fromObjOptions=e1.options;for(var i=0;i<fromObjOptions.length;i++){if(fromObjOptions[i].selected){e2.appendChild(fromObjOptions[i]);i--;}}document.myform.city.value=getvalue(document.myform.list2);}function getvalue(geto){var allvalue = "";for(var i=0;i<geto.options.length;i++){allvalue +=geto.options[i].value + ",";}return allvalue;}function changepos1111(obj,index){if(index==-1){if (obj.selectedIndex>0){obj.options(obj.selectedIndex).swapNode(obj.options(obj.selectedIndex-1))}}else if(index==1){if (obj.selectedIndex<obj.options.length-1){obj.options(obj.selectedIndex).swapNode(obj.options(obj.selectedIndex+1))}}}</script></body></html>
![JS 对select动态添加options操作[IEFireFox兼容]](https://100zi.50zi.cn/uploadfile/img/14/843/7cf0de5b2e721e0b7ea7c672091f4bcc.jpg)
