I am trying to configure this message, which can be deleted by hand with an x at the top, the code is this
<div class="alert alert-warning alert-dismissible fade show" role="alert">
<strong>Holy guacamole!</strong> You should check in on some of those fields below.
<button type="button" class="close" data-dismiss="alert" aria-label="Close">
<span aria-hidden="true">×</span>
</button>
</div>In the documentation says that for this to work you need a util.js library, how can I realize that this library has it installed? and if I do not have it how I install it?