html - div 内的中心加载器

Question

我有这个装载机:

.loader_ajax_small {
  border: 2px solid #f3f3f3 !important;
  border-radius: 50%;
  border-top: 2px solid #2D2D2D !important;
  width: 29px;
  height: 29px;
  -webkit-animation: spin_loader_ajax_small 2s linear infinite;
  animation: spin_loader_ajax_small 2s linear infinite;
}

@-webkit-keyframes spin_loader_ajax_small {
  0% { -webkit-transform: rotate(0deg); }
  100% { -webkit-transform: rotate(360deg); }
}

@keyframes spin_loader_ajax_small {
  0% { transform: rotate(0deg); }
  100% { transform: rotate(360deg); }
}

但我不明白如何在 div 内水平居中，例如:

如您所见，它在左侧，但我希望它居中，我该怎么做？

Answer 1

在 .loader_ajax_small 中为父 div 的中心添加了 margin: 0 auto;

.loader {
  border: 1px solid #ccc;
  padding: 20px;
}
.loader_ajax_small {
  border: 2px solid #f3f3f3 !important;
  border-radius: 50%;
  border-top: 2px solid #2D2D2D !important;
  width: 29px;
  height: 29px;
  margin: 0 auto;
  -webkit-animation: spin_loader_ajax_small 2s linear infinite;
  animation: spin_loader_ajax_small 2s linear infinite;
}

@-webkit-keyframes spin_loader_ajax_small {
  0% { -webkit-transform: rotate(0deg); }
  100% { -webkit-transform: rotate(360deg); }
}

@keyframes spin_loader_ajax_small {
  0% { transform: rotate(0deg); }
  100% { transform: rotate(360deg); }
}

<div class="loader">
  <div class="loader_ajax_small"></div>
</div>

或使用display: flex;

.loader {
  border: 1px solid #ccc;
  padding: 20px;
  display: flex;
  justify-content: center;  
}
.loader_ajax_small {
  border: 2px solid #f3f3f3 !important;
  border-radius: 50%;
  border-top: 2px solid #2D2D2D !important;
  width: 29px;
  height: 29px;
  -webkit-animation: spin_loader_ajax_small 2s linear infinite;
  animation: spin_loader_ajax_small 2s linear infinite;
}

@-webkit-keyframes spin_loader_ajax_small {
  0% { -webkit-transform: rotate(0deg); }
  100% { -webkit-transform: rotate(360deg); }
}

@keyframes spin_loader_ajax_small {
  0% { transform: rotate(0deg); }
  100% { transform: rotate(360deg); }
}

<div class="loader">
  <div class="loader_ajax_small"></div>
</div>