<div ng-class:"{{myclass}}" role="progressbar" aria-valuenow="{{roundedtotalPerformanceCount}}"
aria-valuemin="0" aria-valuemax="100" ng-style="{'width' : ( totalPerformanceCount + '%' ) }">
{{roundedtotalPerformanceCount}} %
</div>
Here is a snippet of code from my controller:
if ($scope.roundedtotalPerformanceCount <= 20)
{
$scope.myclass='progress-bar-below20';
}
else
{
$scope.myclass = 'progress-bar';
}