js获取selec的选中项
var obj = document.getElementById(”select_id”); //selectid
var index = obj.selectedIndex; // 选中索引
var text = obj.options[index].text; // 选中文本
var value = obj.options[index].value; // 选中值
或者
<select id="whichCurrent" runat="server" onchange="changeCurrent(this.options[this.options.selectedIndex].value)"
name="whichCurrent"></select></td>
