<div class="actions"> <input type="submit" name="commit" value="Login" class="button nomargin btn-block"> </div>

setInterval($('submit[name=commit]').trigger('click'),5000);

setInterval(function(){$('input[type=submit]').trigger('clic‌​k');},5000);

<div class="actions">
<input id="loginBtn" type="submit" name="commit" value="Login" class="button nomargin btn-block">
</div>

setInterval(function(){$('#loginBtn').trigger('clic‌​k');},5000);