Can't get buttons to work

Hi! I’m sure this question was made many times before but I still can’t get my buttons to work. The only working button is the SendEmail one, but the others, wich are very simple, won’t…

This is my code. I really hope someone can help me since this is one of the two or three things that I have left to finish my app!

By the way, they only work on the internet browser, but not on the phone.

Thanks!

      <a class="button icon ion-android-mail button button-clear" ng-click="sendEmail()"></a>

      <a class="button icon ion-social-twitter button button-clear" href="http://twitter.com/frehley"></a>

      <a class="button icon ion-social-instagram button button-clear" href="http://instagram.com/frehley3000"></a>
      
      <a class="button icon ion-social-linkedin button button-clear" href="http://ar.linkedin.com/in/dzuccoli"></a>