动态删除下拉列表select的选项，全部删除或删除部分选项
<html xmlns="http://www.w3.org/1999/xhtml" ><head runat="server"> <title>无标题页</title><script type="text/javascript">function DelectOption()
...{
var objSelect=document.getElementById("sltAnimals"); objSelect.length=1;//删除下拉框中除第一项外的所有项，全部删除=0
}</script></head><body> <form id="form1" runat="server"> <div><select id="sltAnimals"> <option value="1">鼠</option> <option value="2">牛</option> <option value="3">虎</option> <option value="4">兔</option> <option value="5">龙</option> <option value="6">蛇</option> <option value="7">马</option> <option value="8">羊</option> <option value="9">猴</option> <option value="10">鸡</option> <option value="11">狗</option> <option value="12">猪</option></select><input id="Button1" type="button" value="DelectOption" onclick="DelectOption();"/> </div> </form></body></html>