var obj = document.getElementByIdx_x_x(”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
js 读取<select>标签选项 索引
原文：http://www.cnblogs.com/dobestself-994395/p/4281094.html
