bigbluebutton-Github/bigbluebutton-html5/app/client/views/sharedTemplates.html

<template name="makeButton">
    <button type="submit" id="{{id}}" class="btn {{btn_class}}" {{isDisabled}} rel="{{rel}}" data-placement="{{data_placement}}" title="{{title}}" style="{{style}}">
      {{#if text}}
        <span>{{text}}</span>
      {{else}}
        {{#if i_class}}
          <i class="{{i_class}}"></i><span>{{label}}</span>
        {{/if}}
      {{/if}}
    </button>
</template>