<ul class="clear">
                        <c:forEach var="item" items="${slotSite }">
                        <li class="${ item.flat eq  code ?  'active': '' }">
                            <c:choose>
                                <c:when test="${item.flat eq 'bbin' }">
                                    <c:choose>
                                        <c:when test="${!empty webUser}">
                                            <a
                                                onclick="winOpen('${ctx}/forwardGame?gameType=bbin&pageSite=game',window.screen.width,window.screen.height,0,0,'game','bbin');return false;"
                                                href="javascript:void(0);" target="_blank" class="block">
                                        </c:when>
                                        <c:otherwise>
                                            <a href="javascript:void(0);"
                                                onclick="alert('您尚未登录，请先登录再进行游戏')" class="block">
                                        </c:otherwise>
                                    </c:choose>BBIN电游</a>
                                </c:when>
                                
                                ***<c:when test="${item.flat  eq 'ag'}">***
                                    <c:choose>
                                        <c:when test="${!empty webUser}">
                                            <a
                                                onclick="winOpen('${ctx}/forwardGame?gameType=ag&agGameType=2',window.screen.width,window.screen.height,0,0,'game','ag');return false;"
                                                href="javascript:void(0);" class="block" target="_blank">
                                        </c:when>
                                        <c:otherwise>
                                            <a href="javascript:void(0);"
                                                onclick="alert('您尚未登录，请先登录再进行游戏')" class="block">
                                        </c:otherwise>
                                    </c:choose>AG电游</a>
                                </c:when>
                                
                                <c:otherwise>
                                    <a href="${ctx}/${item.flatUrl}" class="block">${item.flatName }</a>
                                </c:otherwise>
                            </c:choose>
                        </li>
                        </c:forEach>
                    </ul>

里面的<c:otherwise></c:choose></c:forEach> <c:when test="${item.flat eq 'bbin' }">啥意思？