Angular Bootstrap (UI Bootstrap) provides Angular directives that implement some of Bootstrap's JavaScript components. Using Angular correctly, many of Bootstrap's components will not work natively and require custom directives. UI Bootstrap avoids this issue by implementing the components with Angular directives. While Bootstrap is a CSS framework with some jQuery plugins, Angular manipulates data through binding rather than by grabbing and injecting DOM elements on events like jQuery does, which can conflict. UI Bootstrap at ng-bootstrap.github.io provides common UI components as Angular directives to resolve this conflict.