>Neither modal nor modeless HTML dialog boxes support text selection or the standard shortcut menu for copy operations; however, you can imitate this functionality by using script with TextRange objects and event handlers for onmousedown and onmousemove, ...
This is comically terrible:
https://msdn.microsoft.com/en-us/library/ms536759(v=vs.85).a...
>Neither modal nor modeless HTML dialog boxes support text selection or the standard shortcut menu for copy operations; however, you can imitate this functionality by using script with TextRange objects and event handlers for onmousedown and onmousemove, ...