<!-- Standard button -->

<button type="button" class="btn btn-default">Default</button>

<!-- Provides extra visual weight and identifies the primary action in a set of buttons -->

<button type="button" class="btn btn-primary">Primary</button>

<!-- Indicates a successful or positive action -->

<button type="button" class="btn btn-success">Success</button>

<!-- Contextual button for informational alert messages -->

<button type="button" class="btn btn-info">Info</button>

<!-- Indicates caution should be taken with this action -->

<button type="button" class="btn btn-warning">Warning</button>

<!-- Indicates a dangerous or potentially negative action -->

<button type="button" class="btn btn-danger">Danger</button>

<!-- Deemphasize a button by making it look like a link while maintaining button behavior -->

<button type="button" class="btn btn-link">Link</button>