AngularJS ng-click and ng-class.

HTML

<div ng-app>
    <div 
     class="italic" 
     ng-class="{red: hover}" 
     ng-mouseenter="hover = true"
     ng-mouseleave="hover = false">
         Test 1 2 3.
    </div>
</div>

CSS

.red {
    background-color: red;
}

.italic {
    font-style: italic;
    color: black;
}