How to show loader on the submit button?

Here in this example, I am using the simple bootstrap classes to show the loader on the button? which is I guess very easy and clean.

    

Just use the following code to get the result.

 <button class="btn btn-primary" type="button" disabled> <span class="spinner-border spinner-border-sm" role="status" aria-hidden="true"></span>

  <span class="visually-hidden">Loading...</span>

</button>
<button class="btn btn-primary" type="button" disabled>
<span class="spinner-border spinner-border-sm" role="status" aria-hidden="true"></span>
Loading...
</button>