select标签刷新后保持之前选择值

<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>

<select id="sequence"  > 
   <option value=""></option> 
   <option value="gread" <c:if test="${requestScope.sequence eq 'gread'}">selected="selected"</c:if> >年级</option> 
   <option value="class" <c:if test="${requestScope.sequence eq 'class'}">selected="selected"</c:if>>班级</option>
</select>