title: Display text under cursor
body: <p>Whe mouse pointer placed on an element I want to show some text. For example if you place your cursor on upvote of an answer, it shows "This answer is useful". You can see it in below image. I did't even know how to search this.</p>
  
  <p><img src="https://i.stack.imgur.com/LfIK0.png" alt="enter image description here"></p>