loader in html bootstrap code example

Example 1: circlular waiting icon bootstrap

<div class="spinner-border" role="status">
  <span class="sr-only">Loading...</span>
</div>

Example 2: bootstrap loader

<div class="spinner-grow text-primary" role="status">
  <span class="sr-only">Loading...</span>
</div>
<div class="spinner-grow text-secondary" role="status">
  <span class="sr-only">Loading...</span>
</div>
<div class="spinner-grow text-success" role="status">
  <span class="sr-only">Loading...</span>
</div>
<div class="spinner-grow text-danger" role="status">
  <span class="sr-only">Loading...</span>
</div>
<div class="spinner-grow text-warning" role="status">
  <span class="sr-only">Loading...</span>
</div>
<div class="spinner-grow text-info" role="status">
  <span class="sr-only">Loading...</span>
</div>
<div class="spinner-grow text-light" role="status">
  <span class="sr-only">Loading...</span>
</div>
<div class="spinner-grow text-dark" role="status">
  <span class="sr-only">Loading...</span>
</div>