js select

var obj = document.getElementById("ddlCacheItem"); //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



if (value == '') {

    alert('请选择刷新缓存项目！');

    event.cancelBubble = true;

    event.returnValue = null;

    return false;

}