icon url

Hi,

How I can use an url to get image for button?
I'm triyng that but doesn't change:

`<button class="floating_logout" ng-click="changeDynamicBar($event)" template-url="<c:url value="/get/button/ng-mfb-button-md.tpl.html" />" mfb-button icon="/get/img/floating_btn_icon_log_out.png" label="logout">
                        </button>`

Thanks.
