<a class="twitter-share-button"
  href="https://twitter.com/intent/tweet"
  data-size="large"
  data-text="custom share text"
  data-url="https://dev.twitter.com/web/tweet-button"
  data-hashtags="example,demo"
  data-via="twitterdev"
  data-related="twitterapi,twitter">
Tweet
</a>