You can show/hide practically any element or group of elements with a native button and setting popover=auto will exactly emulate a Flare image popup that can be dismissed by selecting the bounds outside the element.
This has a multitude of uses, but for me personally, it has enabled proper image popups in clean XHTML output.
MDN Docs
Code example:
Line 1: Image shown normally
Line 2: Simple HTML button targeting the ID of the popover element
Line 3: The same image which will be shown in its native size when the button is clicked
Code: Select all
<img src="../../../Resources/Images/Example-Image.png" alt="Some alt text" />
<button popovertarget="image1">Click to Expand</button>
<img popover="auto" id="image1" src="../../../Resources/Images/Example-Image.png" alt="Some alt text" />