AJAX——图片上传

图片上传流程

1.获取图片文件对象

2.使用FormData携带图片文件

3.提交表单数据到服务器，使用图片url网址

<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>图片上传</title>
</head>

<body>
  <!-- 文件选择元素 -->
  <input type="file" class="upload">
  <img src="" alt="" class="my-img">

  <script src="https://cdn.jsdelivr.net/npm/axios/dist/axios.min.js"></script>
  <script>
    /**
     * 目标：图片上传，显示到网页上
     *  1. 获取图片文件
     *  2. 使用 FormData 携带图片文件
     *  3. 提交到服务器，获取图片url网址使用
    */
    // 文件选择元素->change改变事件
    document.querySelector('.upload').addEventListener('change', e => {
      // 1. 获取图片文件
      console.log(e.target.files[0])
      // 2. 使用 FormData 携带图片文件
      const fd = new FormData()
      fd.append('img', e.target.files[0])
      // 3. 提交到服务器，获取图片url网址使用
      axios({
        url: 'http://hmajax.itheima.net/api/uploadimg',
        method: 'POST',
        data: fd
      }).then(result => {
        console.log(result)
        // 取出图片url网址，用img标签加载显示
        const imgUrl = result.data.data.url
        document.querySelector('.my-img').src = imgUrl
      })
    })
  </script>
</body>

</html>

案例网站-更换背景

1.选择图片上传，设置body背景

2.上传成功时，保存url网址

3.网页运行后，获取url网址使用

/**
 * 目标：网站-更换背景
 *  1. 选择图片上传，设置body背景
 *  2. 上传成功时，"保存"图片url网址
 *  3. 网页运行后，"获取"url网址使用
 * */
document.querySelector('.bg-ipt').addEventListener('change', e => {
  // 1. 选择图片上传，设置body背景
  console.log(e.target.files[0])
  const fd = new FormData()
  fd.append('img', e.target.files[0])
  axios({
    url: 'http://hmajax.itheima.net/api/uploadimg',
    method: 'POST',
    data: fd
  }).then(result => {
    const imgUrl = result.data.data.url
    document.body.style.backgroundImage = `url(${imgUrl})`


    // 2. 上传成功时，"保存"图片url网址
    localStorage.setItem('bgImg', imgUrl)
  })
})

// 3. 网页运行后，"获取"url网址使用
const bgUrl = localStorage.getItem('bgImg')
console.log(bgUrl)
// 本地有背景图地址才设置
bgUrl && (document.body.style.backgroundImage = `url(${bgUrl})`)

index.html

<!DOCTYPE html>
<html lang="zh-CN">

<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>网站-更换背景</title>
  <!-- 初始化样式 -->
  <link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/reset.css@2.0.2/reset.min.css">
  <!-- 核心样式 -->
  <link rel="stylesheet" href="./css/index.css">
</head>

<body>
  <div class="container">
    <div class="nav">
      <div class="left">
        <ul>
          <li><a href="http://yun.itheima.com/?webzly" target="_blank" rel="nofollow">免费教程</a></li>
          <li><a href="http://resource.ityxb.com/booklist/?webzly" target="_blank" rel="nofollow">原创书籍</a></li>
          <li><a href="http://www.itheima.com/teacher.html?webzly#ajavaee" target="_blank" rel="nofollow">教研团队</a></li>
          <li><a href="http://www.itheima.com/special/hmschool/index.shtml?webzly" target="_blank" rel="nofollow">校区汇总</a></li>
          <li><a href="http://www.itheima.com/flow/flow.html?webzly" target="_blank" rel="nofollow">报名流程</a></li>
          <li><a href="https://pip.itcast.cn?hmgw$webzly" target="_blank" rel="nofollow">项目信息站</a></li>
          <li><a href="http://bbs.itheima.com/forum.php?webzly" target="_blank" rel="nofollow">技术社区</a></li>
        </ul>
      </div>
      <div class="right">
        <label for="bg">更换背景</label>
        <input class="bg-ipt" type="file" id="bg">
      </div>
    </div>
    <div class="search-container">
      <img src="https://www.itheima.com/images/logo.png" alt="">
      <div class="search-box">
        <input type="text">
        <button>搜索一下</button>
      </div>
    </div>
  </div>
  <script src="https://cdn.jsdelivr.net/npm/axios/dist/axios.min.js"></script>
  <!-- 核心代码 -->
  <script src="./js/index.js"></script>
</body>

</html>

index.css

html,
body {
  height: 100%;
  font-size: 14px;
}

.nav {
  height: 60px;
  background: rgba(0, 0, 0, 0.2);
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 0 20px;
}

.nav ul {
  display: flex;
}

.nav ul li {
  margin-right: 10px;
  cursor: pointer;
}

.nav ul li a {
  color: white;
  text-decoration: none;
}

.nav .right label {
  background: #edf2f5;
  padding: 5px 10px;
  border-radius: 10px;
  font-size: 12px;
  cursor: pointer;
}

.nav .right input {
  display: none;
}

.search-container {
  position: absolute;
  top: 30%;
  left: 50%;
  transform: translate(-50%, -50%);
  text-align: center;
}

.search-container .search-box {
  display: flex;
}

.search-container img {
  margin-bottom: 30px;
}


.search-container .search-box input {
  width: 512px;
  height: 16px;
  padding: 12px 16px;
  font-size: 16px;
  margin: 0;
  vertical-align: top;
  outline: 0;
  box-shadow: none;
  border-radius: 10px 0 0 10px;
  border: 2px solid #c4c7ce;
  background: #fff;
  color: #222;
  overflow: hidden;
  box-sizing: content-box;
  -webkit-tap-highlight-color: transparent;
}

.search-container .search-box button {
  cursor: pointer;
  width: 112px;
  height: 44px;
  line-height: 41px;
  line-height: 42px;
  background-color: #ad2a27;
  border-radius: 0 10px 10px 0;
  font-size: 17px;
  box-shadow: none;
  font-weight: 400;
  border: 0;
  outline: 0;
  letter-spacing: normal;
  color: white;
}

body {
  background: no-repeat center /cover;
  background-color: #edf0f5;
}