title: How to blur arbitrary area on web page?
body: <p>Is there any feasible solution to blur any arbitrary areas on web page (include but not limited to image, element)?</p>
  
  <p>Just like this, or many blurred popovers on iOS:
  <a href="https://i.stack.imgur.com/QpKIe.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/QpKIe.png" alt="enter image description here"></a></p>