Alerts
Bootstrap provides an easy way to create predefined alert messages:
Alerts are created with the .alert class, followed by one of the four contextual classes .alert-success, .alert-info, .alert-warning or .alert-danger:
EXAMPLE:
<div class="alert alert-success">
<strong>Success!</strong> Indicates a successful or positive action.
</div>
<div class="alert alert-info">
<strong>Info!</strong> Indicates a neutral informative change or action.
</div>
<div class="alert alert-warning">
<strong>Warning!</strong> Indicates a warning that might need attention.
</div>
<div class="alert alert-danger">
<strong>Danger!</strong> Indicates a dangerous or potentially negative action.
</div>

Alert Links
Add the alert-link class to any links inside the alert box to create "matching colored links":
EXAMPLE:
<div class="alert alert-success">
<strong>Success!</strong> You should <a href="#" class="alert-link">read this message</a>.
</div>

Closing Alerts
To close the alert message, add a .alert-dismissible class to the alert container. Then add class="close" and data-dismiss="alert" to a link or a button element (when you click on this the alert box will disappear).
EXAMPLE:
<div class="alert alert-success alert-dismissible">
<a href="#" class="close" data-dismiss="alert" aria-label="close">×</a>
<strong>Success!</strong> Indicates a successful or positive action.
</div>

Animated Alerts
The .fade and .in classes adds a fading effect when closing the alert message:
EXAMPLE:
<div class="alert alert-danger fade in">
