<select id="selectId">
  <option value="orange">橙色</option>
  <option value="yellow">黄色</option>
</select>

获取value值

var color = $("#selectId").val();
var color = $("#selectId option:selected").val();
var color = $("#selectId").find("option:selected").val();
var color = $("#selectId option:selected").attr("value");

获取text值

var color1 = $("#selectId option:selected").text();
var color1 = $("#selectId").find("option:selected").text();