<script src="//platform.twitter.com/oct.js" type="text/javascript"></script>
<script type="text/javascript">twttr.conversion.trackPid('l6ngp', { tw_sale_amount: 0, tw_order_quantity: 0 });</script>
<noscript>
<img height="1" width="1" style="display:none;" alt="" src="https://analytics.twitter.com/i/adsct?txn_id=l6ngp&p_id=Twitter&tw_sale_amount=0&tw_order_quantity=0" />
<img height="1" width="1" style="display:none;" alt="" src="//t.co/i/adsct?txn_id=l6ngp&p_id=Twitter&tw_sale_amount=0&tw_order_quantity=0" />
</noscript>

<script src="//platform.twitter.com/oct.js" type="text/javascript"></script>
<script type="text/javascript">
  if (typeof(twttr) !== "undefined") {
    twttr.conversion.trackPid('l6ngp', { tw_sale_amount: 0, tw_order_quantity: 0 });
  }
</script>
<noscript>
<img height="1" width="1" style="display:none;" alt="" src="https://analytics.twitter.com/i/adsct?txn_id=l6ngp&p_id=Twitter&tw_sale_amount=0&tw_order_quantity=0" />
<img height="1" width="1" style="display:none;" alt="" src="//t.co/i/adsct?txn_id=l6ngp&p_id=Twitter&tw_sale_amount=0&tw_order_quantity=0" />
</noscript>

Make sure twitter is defined first.
Make sure twitter is defined first.
