jQuery : quelques exemples

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

.loader {
  border: 16px solid #f3f3f3; /* Light grey */
  border-top: 16px solid #3498db; /* Blue */
  border-radius: 50%;
  width: 120px;
  height: 120px;
  animation: spin 2s linear infinite;
}

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

  .loader1 {
    border-top: 16px solid blue;
    border-bottom: 16px solid blue;
  }
  .loader2 {
    border-top: 16px solid blue;
    border-right: 16px solid green;
    border-bottom: 16px solid red;
  }
  .loader3 {
    border-top: 16px solid blue;
    border-right: 16px solid green;
    border-bottom: 16px solid red;
    border-left: 16px solid pink;
  }