<script language="JavaScript" type="text/javascript">
<!--
/*
 * 說明：將指定下拉列表的選項值清空
 * 轉(zhuǎn)自：Gdong Elvis ( http://www.gdcool.net )
 *
 * @param {String || Object]} selectObj 目標(biāo)下拉選框的名稱或?qū)ο螅仨?
 */
 function removeOptions(selectObj)
 {
 if (typeof selectObj != 'object')
 {
 selectObj = document.getElementById(selectObj);
 }
 // 原有選項計數(shù)
 var len = selectObj.options.length;
 for (var i=0; i < len; i++) {
 // 移除當(dāng)前選項
 selectObj.options[0] = null;
 }
 }
 /*
 * @param {String || Object]} selectObj 目標(biāo)下拉選框的名稱或?qū)ο?，必?
 * @param {Array} optionList 選項值設(shè)置 格式：[{txt:'北京', val:'010'}, {txt:'上海', val:'020'}] ，必須
 * @param {String} firstOption 第一個選項值，如：“請選擇”，可選，值為空
 * @param {String} selected 默認(rèn)選中值，可選
 */
 function setSelectOption(selectObj, optionList, firstOption, selected) {
 if (typeof selectObj != 'object')
 {
 selectObj = document.getElementById(selectObj);
 }
 // 清空選項
 removeOptions(selectObj);
 // 選項計數(shù)
 var start = 0;
 // 如果需要添加第一個選項
 if (firstOption) {
 selectObj.options[0] = new Option(firstOption, '');
 // 選項計數(shù)從 1 開始
 start ++;
 }
 var len = optionList.length;
 for (var i=0; i < len; i++) {
 // 設(shè)置 option
 selectObj.options[start] = new Option(optionList[i].txt, optionList[i].val);
 // 選中項
 if(selected == optionList[i].val)  {
 selectObj.options[start].selected = true;
 }
 // 計數(shù)加 1
 start ++;
 }
 }
 //-->
</script>
<script language="JavaScript" type="text/javascript">
var cityArr = [];
cityArr['江蘇省'] =
[
 {txt:'南京', val:'南京'},
 {txt:'無錫', val:'無錫'},
 {txt:'徐州', val:'徐州'},
 {txt:'蘇州', val:'蘇州'},
 {txt:'南通', val:'南通'},
 {txt:'淮陰', val:'淮陰'},
 {txt:'揚州', val:'揚州'},
 {txt:'鎮(zhèn)江', val:'鎮(zhèn)江'},
 {txt:'常州', val:'常州'}
 ];
cityArr['浙江省'] =
[
 {txt:'杭州', val:'杭州'},
 {txt:'寧波', val:'寧波'},
 {txt:'溫州', val:'溫州'},
 {txt:'湖州', val:'湖州'}
 ];
function setCity(province)
{
 setSelectOption('city', cityArr[province], '-請選擇-');
}
</script>
 <select name="province" id="province" onchange="if(this.value != '') setCity(this.options[this.selectedIndex].value);">
 <option value="">-請選擇-</option>
 <option value="江蘇省">江蘇省</option>
 <option value="浙江省">浙江省</option>
 </select>
 省
 <select name="city" id="city">
 <option value="">-請選擇-</option>
 </select>
 市