On the difficulties of creating modal dialog boxes for the web

[cvrebert]

• Don't scroll the page when showing/hiding the modal
• Don't allow the underlying page to be scrolled while the modal is open
• If showing the modal adds/removes the scrollbar, prevent the page from shifting or resizing as a result
• Handle modal content which is taller than the viewport
• Stealing the focus and conflicts with other plugins that want to manage the focus (e.g. Select2)
• z-index
• Weird zooming when an input in the modal is focused on mobile
• The iPad <select>-within-modal bug
• Survey other modal libraries to see which of these features they lack