I was trying to run a query in Data Explorer without logging in (I didn't notice that I am not logged in). When I click on Run Query button, I got a Captcha to avoid spam queries. But what I found that there is a Textbox instead of a Button for I'm a Human Being.
The Textbox is not ideal option for that. So there should be a button instead of Textbox like this one:
<a id="nav-askquestion" href="/questions/ask">Ask Question</a>
, inside a<div><ul>
. I would imagine the Captcha "button" is something similar.