Use your mouse to drag a *.html file from your computer's desktop over the three coloured squares on this page. The mouse cursor should appear as a "drop-allowed" cursor over all three squares.
Release the drag over the pink square. If a prompt appears, accept it. The cursor should revert to the default mouse cursor.

This test only applies to platforms with a mouse cursor that can change to indicate drop status.

This test assumes the browser will open dropped files natively if they are not handled by a script.