javascript 09年最新版的省市联动

<select id="province" onchange="setcity(this.value);getarea()" name="province"><option value="" selected>请选择 </option></select><select id="city" onchange="setcounty(this.value);getarea()" name="city" style="display:;"><option value="" selected>请选择 </option></select><select id="county" name="county" onchange="getarea()" style="display:;"><option value="" selected>请选择 </option></select><input type="text" name="area" id="area" value="222426" onchange="setarea();"><input type="button" value="转" onclick="setarea();">
[ctrl+a 全选 注:如需引入外部js需刷新才能执行]