Twitter sharing prompt opens both in a new window, and a new tab

[stefanbohacek]

In Firefox (version 50.0.1), when I click the twitter button, it opens both in a new window, and a new tab.

As you can see, the one in the tab is missing the Twitter handle, and the one that opens in a new window is missing everything else.

A quick fix for this would be handling the onclick event using addEventListener instead of the inline script, so that you can use preventDefault.