<div :class="2 == 1 ? 'left' : 2 == 2 ? 'left center' : 'left right'" style="backgroundColor: rgba(74, 204, 64, 0.25)">

这是一个Vue.js的代码片段，其中使用了三元运算符来根据条件设置CSS类。如果条件2等于1，则该元素将具有“left”类，否则如果条件2等于2，则该元素将具有“left center”类，否则将具有“left right”类。此外，该元素的背景颜色设置为RGBA值（74, 204, 64, 0.25）的半透明绿色。

相关问题

鼠标略过白色方框选项时，为每一个选项添加与头部导航栏相同的背景颜色，同时设置字体颜色为白色；尽可能与图片效果保持一致。功能要求：①鼠标略出头像及白色方框区域时，白色方框消失；②头像右侧显示存储在本地存储中的用户名称，③点击退出登录，清除在本地存储中的数据并跳转到登陆页面。

以下是实现该功能的代码示例：

HTML代码：

<header>
  <div class="logo"></div>
  <div class="user">
    <div class="avatar"></div>
    <div class="username"></div>
    <div class="options">
      <div class="option">选项1</div>
      <div class="option">选项2</div>
      <div class="option">选项3</div>
      <div class="option">选项4</div>
      <div class="logout">退出登录</div>
    </div>
  </div>
</header>

CSS代码：

header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  background-color: #f7f7f7;
  padding: 20px;
}

.logo {
  width: 50px;
  height: 50px;
  background-image: url("logo.png");
  background-size: cover;
  background-position: center;
}

.user {
  display: flex;
  align-items: center;
  position: relative;
}

.avatar {
  width: 40px;
  height: 40px;
  background-image: url("avatar.png");
  background-size: cover;
  background-position: center;
  border-radius: 50%;
  cursor: pointer;
}

.username {
  margin-left: 10px;
  font-size: 16px;
  font-weight: bold;
}

.options {
  display: none;
  position: absolute;
  top: 50px;
  right: 0;
  width: 150px;
  background-color: #f7f7f7;
  box-shadow: 0 0 5px rgba(0, 0, 0, 0.2);
  z-index: 999;
}

.option {
  padding: 10px;
  cursor: pointer;
}

.option:hover {
  background-color: #007bff;
  color: #fff;
}

.logout {
  padding: 10px;
  cursor: pointer;
  background-color: #dc3545;
  color: #fff;
}

.logout:hover {
  background-color: #c82333;
}

JavaScript代码：

// 获取相关元素
const avatar = document.querySelector(".avatar");
const options = document.querySelector(".options");
const optionList = document.querySelectorAll(".option");
const logout = document.querySelector(".logout");
const username = document.querySelector(".username");

// 鼠标移入头像时显示选项菜单
avatar.addEventListener("mouseover", function() {
  options.style.display = "block";
});

// 鼠标移出头像和选项菜单时隐藏选项菜单
avatar.addEventListener("mouseout", function() {
  options.style.display = "none";
});

options.addEventListener("mouseover", function() {
  options.style.display = "block";
});

options.addEventListener("mouseout", function() {
  options.style.display = "none";
});

// 鼠标移入选项时改变背景颜色和字体颜色
optionList.forEach(function(option) {
  option.addEventListener("mouseover", function() {
    option.style.backgroundColor = "#007bff";
    option.style.color = "#fff";
  });
  
  option.addEventListener("mouseout", function() {
    option.style.backgroundColor = "transparent";
    option.style.color = "#000";
  });
});

// 点击退出登录时清除本地存储并跳转到登录页面
logout.addEventListener("click", function() {
  localStorage.clear();
  window.location.href = "login.html";
});

// 从本地存储中获取用户名并显示
const storedUsername = localStorage.getItem("username");
if (storedUsername) {
  username.textContent = storedUsername;
}

uniapp tabBar换到顶上

为了将uniapp的tabBar换到顶部，我们需要进行以下步骤：

1.在App.vue中添加以下代码：

<template>
  <div>
    <tab-bar></tab-bar>
    <router-view></router-view>
  </div>
</template>

<script>
import tabBar from '@/components/tabBar.vue'

export default {
  components: {
    tabBar
  }
}
</script>

2.在tabBar.vue中添加以下代码：

<template>
  <div class="tab-bar">
    <div class="tab-bar-item" v-for="(item, index) in tabList" :key="index" @click="switchTab(index)">
      <img :src="item.iconPath" :class="activeIndex === index ? 'active' : ''">
      <p :class="activeIndex === index ? 'active' : ''">{{ item.text }}</p>
    </div>
  </div>
</template>

<script>
export default {
  data() {
    return {
      activeIndex: 0,
      tabList: [
        {
          iconPath: '/static/tabBar/home.png',
          selectedIconPath: '/static/tabBar/home-active.png',
          text: '首页',
          pagePath: '/pages/index/index'
        },
        {
          iconPath: '/static/tabBar/mine.png',
          selectedIconPath: '/static/tabBar/mine-active.png',
          text: '我的',
          pagePath: '/pages/mine/mine'
        }
      ]
    }
  },
  methods: {
    switchTab(index) {
      this.activeIndex = index
      uni.switchTab({
        url: this.tabList[index].pagePath
      })
    }
  }
}
</script>

<style>
.tab-bar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: 100px;
  background-color: #fff;
  box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

.tab-bar-item {
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  width: 50%;
  height: 100%;
}

.tab-bar-item img {
  width: 40px;
  height: 40px;}

.tab-bar-item p {
  font-size: 24px;
  margin-top: 10px;
}

.tab-bar-item img.active {
  width: 50px;
  height: 50px;
}

.tab-bar-item p.active {
  color: #007aff;
}
</style>

3.在pages.json中添加以下代码：

{
  "globalStyle": {
    "navigationBarTextStyle": "white",
    "navigationBarTitleText": "核心圈",
    "navigationBarBackgroundColor": "#009cfd",
    "backgroundColor": "#ff12e9"
  },
  "tabBar": {
    "position": "top",
    "color": "#7A7E83",
    "selectedColor": "#007aff",
    "backgroundColor": "#ffffff",
    "borderStyle": "black",
    "list": [
      {
        "pagePath": "pages/index/index",
        "text": "首页",
        "iconPath": "static/tabBar/home.png",
        "selectedIconPath": "static/tabBar/home-active.png"
      },
      {
        "pagePath": "pages/mine/mine",
        "text": "我的",
        "iconPath": "static/tabBar/mine.png",
        "selectedIconPath": "static/tabBar/mine-active.png"
      }
    ]
  }
}