element ui 導(dǎo)航欄跳轉(zhuǎn)之后怎么讓跳轉(zhuǎn)的頁也顯示導(dǎo)航？

<div>
        <div class="nav">
            <div class="icon">132</div>
            <el-menu :default-active="activeIndex === '' ? '/' : activeIndex" class="el-menu-demo" mode="horizontal" @select="handleSelect" router>
                <el-menu-item index="/" icon="el-icon-search">1</el-menu-item>
                <el-submenu index="2">
                    <template slot="title">2</template>
                    <el-menu-item index="2-1">2-1</el-menu-item>
                </el-submenu>
                <el-menu-item index="3">3</el-menu-item>
                <el-menu-item index="4">4</el-menu-item>
            </el-menu>
            <div style="clear: both;"></div>
        </div>
        <div class="show">
            <hello-world></hello-world>
        </div>
    </div>