Undoing some changes made some weeks back: the #share_url text area, on mobile,
is now a DIV with some styling to look like a text field. On iOS the real text inputs cannot be copied effectively,
iOS grabs a bunch of other cruft (styling codes?) so the URL can't be usefully pasted.

Using a plain text DIV, works fine. But will run the risk of a very-long URL overflowing it.