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css - 将 div 预加载器覆盖到部分元素

问题描述

我需要在元素的中心添加一个 div 预加载article器！

我不希望这个预加载器扩展到整个主体，因为侧面菜单是静态的！

因此，我希望它只占用article元素并覆盖 section元素，直到此部分中的数据准备好在请求后显示。

我创建了一个示例，使用 setTimout 模拟预加载器显示时间。

但是，在示例中，预加载器并未与该部分重叠，而是将其向下推。

<!DOCTYPE html>
<html>
  <head>  
    <meta charset="utf-8">
        <title>Template</title>
        <meta name="description" content="Description of site" />
        <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/css/bootstrap.min.css" integrity="sha384-Gn5384xqQ1aoWXA+058RXPxPg6fy4IWvTNh0E263XmFcJlSAwiGgFAW/dAiS6JXm" crossorigin="anonymous">
    </head> 
    <body>
        <div class="content">
            <header id="header">
            </header>
            <main id="main">
                <nav id="nav-left">
                </nav>
                <article id="article">
                    <div id="breadcrumb">
                        <nav aria-label="breadcrumb">
                            <ol class="breadcrumb">
                                <li class="breadcrumb-item active" aria-current="page">Dashboard</li>
                            </ol>
                        </nav>
                    </div>
                    <div id="preloader" class="page-loader-wrapper">
                        <div class="loader">
                            <div class="loader-wheel"></div>
                            <div class="loader-text"></div>
                        </div>
                    </div>
                    <section id="section"></section>
                    <footer id="footer">Footer</footer>
                </article>
            </main>
        </div>            
        <script src="https://code.jquery.com/jquery-3.2.1.slim.min.js" integrity="sha384-KJ3o2DKtIkvYIK3UENzmM7KCkRr/rE9/Qpg6aAZGJwFDMVNA/GpGFF93hXpG5KkN" crossorigin="anonymous"></script>
        <script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.12.9/umd/popper.min.js" integrity="sha384-ApNbgh9B+Y1QKtv3Rn7W3mgPxhU9K/ScQsAP7hUibX39j7fakFPskvXusvfa0b4Q" crossorigin="anonymous"></script>
        <script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/js/bootstrap.min.js" integrity="sha384-JZR6Spejh4U02d8jOt6vLEHfe/JQGiRRSQQxSfFWpi1MquVdAyjUar5+76PVCmYl" crossorigin="anonymous"></script>
        <script>
            let loader = document.getElementById('preloader');
            setTimeout(function(){ loader.style.display = 'none'; }, 1500);
        </script>
    </body>
</html>
<style>
body {
    height: 100vh;
    width: 100%;
    overflow: hidden;
}
#content {
    background-color: #fff;
    display: -webkit-box;
    display: -ms-flexbox;
    display: flex;
    -webkit-box-orient: vertical;
    -webkit-box-direction: normal;
    -ms-flex-direction: column;
    flex-direction: column;
    height: 100%;
}
#header {
    border-bottom: 1px solid transparent;
    background-color: #404bb3;
    color: #fff;
}
@media (min-width: 768px) {
    #header {
        height: 3.5rem;
    }
}
@media (min-width: 768px) {
    #main {
        height: calc(100vh - 3.5rem);
    }
}
#main {
    display: -webkit-box;
    display: -ms-flexbox;
    display: flex;
    height: calc(100vh - 3rem);
    z-index: 0;
}
@media (min-width: 768px) {
    #nav-left {
        position: relative;
    }
}
#nav-left {
    background-color: #fff;
    border-right: 1px solid #000;
    z-index: 9000;
    min-width: 15.625rem;
    display: -webkit-box;
    display: -ms-flexbox;
    display: flex;
    -webkit-box-orient: vertical;
    -webkit-box-direction: normal;
    -ms-flex-direction: column;
    flex-direction: column;
    -webkit-box-pack: justify;
    -ms-flex-pack: justify;
    justify-content: space-between;
    -webkit-transition: all 0.2s ease-in-out;
    transition: all 0.2s ease-in-out;
}
@media (min-width: 768px) {
    #article {
        -webkit-transition: all 0.2s ease-in-out;
        transition: all 0.2s ease-in-out;
        width: calc(100vw - 15.625rem);
    }
}
#article {
    -webkit-box-flex: 1;
    -ms-flex: 1;
    flex: 1;
    width: 100%;
    display: -webkit-box;
    display: -ms-flexbox;
    display: flex;
    -webkit-box-orient: vertical;
    -webkit-box-direction: normal;
    -ms-flex-direction: column;
    flex-direction: column;
}
#breadcrumb {
    border-bottom: 1px solid #000;
    padding: 0 15px;
    -webkit-box-flex: 0;
    -ms-flex: 0 1 3rem;
    flex: 0 1 3rem;
    display: -webkit-box;
    display: -ms-flexbox;
    display: flex;
    -webkit-box-align: center;
    -ms-flex-align: center;
    align-items: center;
}
.breadcrumb {
    background-color: transparent;
    margin: 0;
    padding: 0;
}

/* loading */
.page-loader-wrapper {
    align-items: center;
    background-color: black;
    display: flex;
    height: 87%;
    justify-content: center;
    margin: 0;
    opacity: 0.5;
}
.loader {
    width: 60px;
}
.loader-wheel {
    animation: spin 1s infinite linear;
    border: 2px solid rgb(212 216 245);
    border-left: 4px solid #404bb3;
    border-radius: 50%;
    height: 50px;
    margin-bottom: 10px;
    width: 50px;
}
.loader-text {
    color: #404bb3;
    font-family: arial, sans-serif;
}
#section {
    background-color: #9932cc;
    border-bottom: 1px solid #000;
    -webkit-box-flex: 1;
    -ms-flex: 1;
    flex: 1;
    padding: 15px 0;
    display: -webkit-box;
    display: -ms-flexbox;
    display: flex;
    -webkit-box-orient: vertical;
    -webkit-box-direction: normal;
    -ms-flex-direction: column;
    flex-direction: column;
    overflow-x: hidden;
    overflow-y: auto;
}
@media (min-width: 768px) {
    #footer {
        padding: 0 1rem;
        -webkit-box-pack: justify;
        -ms- flex-pack: justify;
        justify-content: space-between;
    }
}
#footer {
    font-size: 80%;
    -webkit-box-flex: 0;
    -ms-flex: 0 1 3rem;
    flex: 0 1 3rem;
    display: -webkit-box;
    display: -ms-flexbox;
    display: flex;
    -webkit-box-pack: center;
    -ms-flex-pack: center;
    justify-content: center;
    -webkit-box-align: center;
    -ms-flex-align: center;
    align-items: center;
}
</style>

在此处输入图像描述

标签： css

解决方案

为此，我将执行以下操作：

  1. 使section position: relative;
  2. 从 DOM 中删除preloader，因此仅在需要时添加
  3. 移动 的prelaoder内部section，因此可以相对于它定位（当它出现时）
  4. 修改preloaderCSS，使其position: absolute;

// extract preloader from DOM
const preloader = `
  <div id="preloader" class="page-loader-wrapper">
    <div class="loader">
      <div class="loader-wheel"></div>
      <div class="loader-text"></div>
    </div>
  </div>
`

$('#addPreloader').on('click', function() {
  // add preloader
  $('#section').append(preloader);
  // remove preloader after 1500 ms
  setTimeout(function() {
    $('#preloader').remove()
  }, 1500);
})
body {
  height: 100vh;
  width: 100%;
  overflow: hidden;
}

#content {
  background-color: #fff;
  display: -webkit-box;
  display: -ms-flexbox;
  display: flex;
  -webkit-box-orient: vertical;
  -webkit-box-direction: normal;
  -ms-flex-direction: column;
  flex-direction: column;
  height: 100%;
}

#header {
  border-bottom: 1px solid transparent;
  background-color: #404bb3;
  color: #fff;
}

@media (min-width: 768px) {
  #header {
    height: 3.5rem;
  }
}

@media (min-width: 768px) {
  #main {
    height: calc(100vh - 3.5rem);
  }
}

#main {
  display: -webkit-box;
  display: -ms-flexbox;
  display: flex;
  height: calc(100vh - 3rem);
  z-index: 0;
}

@media (min-width: 768px) {
  #nav-left {
    position: relative;
  }
}

#nav-left {
  background-color: #fff;
  border-right: 1px solid #000;
  z-index: 9000;
  min-width: 15.625rem;
  display: -webkit-box;
  display: -ms-flexbox;
  display: flex;
  -webkit-box-orient: vertical;
  -webkit-box-direction: normal;
  -ms-flex-direction: column;
  flex-direction: column;
  -webkit-box-pack: justify;
  -ms-flex-pack: justify;
  justify-content: space-between;
  -webkit-transition: all 0.2s ease-in-out;
  transition: all 0.2s ease-in-out;
}

@media (min-width: 768px) {
  #article {
    -webkit-transition: all 0.2s ease-in-out;
    transition: all 0.2s ease-in-out;
    width: calc(100vw - 15.625rem);
  }
}

#article {
  -webkit-box-flex: 1;
  -ms-flex: 1;
  flex: 1;
  width: 100%;
  display: -webkit-box;
  display: -ms-flexbox;
  display: flex;
  -webkit-box-orient: vertical;
  -webkit-box-direction: normal;
  -ms-flex-direction: column;
  flex-direction: column;
}

#breadcrumb {
  border-bottom: 1px solid #000;
  padding: 0 15px;
  -webkit-box-flex: 0;
  -ms-flex: 0 1 3rem;
  flex: 0 1 3rem;
  display: -webkit-box;
  display: -ms-flexbox;
  display: flex;
  -webkit-box-align: center;
  -ms-flex-align: center;
  align-items: center;
}

.breadcrumb {
  background-color: transparent;
  margin: 0;
  padding: 0;
}


/* loading */

.page-loader-wrapper {
  align-items: center;
  background-color: black;
  display: flex;
  justify-content: center;
  margin: 0;
  opacity: 0.5;
  height: 100%;
  width: 100%;
  position: absolute;
  top: 0;
  left: 0;
}

.loader {
  width: 60px;
}

.loader-wheel {
  animation: spin 1s infinite linear;
  border: 2px solid rgb(212 216 245);
  border-left: 4px solid #404bb3;
  border-radius: 50%;
  height: 50px;
  margin-bottom: 10px;
  width: 50px;
}

.loader-text {
  color: #404bb3;
  font-family: arial, sans-serif;
}

#section {
  background-color: #9932cc;
  border-bottom: 1px solid #000;
  -webkit-box-flex: 1;
  -ms-flex: 1;
  flex: 1;
  padding: 15px 0;
  display: -webkit-box;
  display: -ms-flexbox;
  display: flex;
  -webkit-box-orient: vertical;
  -webkit-box-direction: normal;
  -ms-flex-direction: column;
  flex-direction: column;
  overflow-x: hidden;
  overflow-y: auto;
  position: relative;
}

@media (min-width: 768px) {
  #footer {
    padding: 0 1rem;
    -webkit-box-pack: justify;
    -ms- flex-pack: justify;
    justify-content: space-between;
  }
}

#footer {
  font-size: 80%;
  -webkit-box-flex: 0;
  -ms-flex: 0 1 3rem;
  flex: 0 1 3rem;
  display: -webkit-box;
  display: -ms-flexbox;
  display: flex;
  -webkit-box-pack: center;
  -ms-flex-pack: center;
  justify-content: center;
  -webkit-box-align: center;
  -ms-flex-align: center;
  align-items: center;
}
<!DOCTYPE html>

<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/css/bootstrap.min.css" integrity="sha384-Gn5384xqQ1aoWXA+058RXPxPg6fy4IWvTNh0E263XmFcJlSAwiGgFAW/dAiS6JXm" crossorigin="anonymous">
<div class="content">
  <header id="header">
  </header>
  <main id="main">
    <nav id="nav-left">
    </nav>
    <article id="article">
      <div id="breadcrumb">
        <nav aria-label="breadcrumb">
          <ol class="breadcrumb">
            <li class="breadcrumb-item active" aria-current="page">Dashboard</li>
          </ol>
        </nav>
      </div>
      <section id="section"></section>
      <footer id="footer">
        Footer
        <button id="addPreloader">ADD PRELOADER</button>
      </footer>
    </article>
  </main>
</div>
<script src="https://code.jquery.com/jquery-3.2.1.slim.min.js" integrity="sha384-KJ3o2DKtIkvYIK3UENzmM7KCkRr/rE9/Qpg6aAZGJwFDMVNA/GpGFF93hXpG5KkN" crossorigin="anonymous"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.12.9/umd/popper.min.js" integrity="sha384-ApNbgh9B+Y1QKtv3Rn7W3mgPxhU9K/ScQsAP7hUibX39j7fakFPskvXusvfa0b4Q" crossorigin="anonymous"></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/js/bootstrap.min.js" integrity="sha384-JZR6Spejh4U02d8jOt6vLEHfe/JQGiRRSQQxSfFWpi1MquVdAyjUar5+76PVCmYl" crossorigin="anonymous"></script>

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