$('.line').click(function() {_x000D_
$(this).toggleClass('red');_x000D_
});
_x000D_
.line {_x000D_
border: 0;_x000D_
background-color: #000;_x000D_
height: 3px;_x000D_
cursor: pointer;_x000D_
}_x000D_
.red {_x000D_
background-color: red;_x000D_
}
_x000D_
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>_x000D_
<hr class="line"></hr>_x000D_
<p>click the line</p>
_x000D_