Enter ng-class object. First (highlight) will be the class added to the element:
<div ng-class="{highlight:onOff}"> Highlight this box </div>
When pressed button element will toggle class inside element with ng-class:
<button ng-click="onOff=!onOff">Toggle</button>
Another example:
<p ng-click="onOff=!onOff" ng-class="{highlight:onOff}" ng-repeat="todo in todos | filter:search"> @{{todo.todo}} </p>