Selection.applescript

use sys : application "System Events"

-- Use the following delay to choose an application window
-- and highlight some text.  Then ensure that the window remains
-- in focus until the script terminates.
delay 5

set P to the first process whose frontmost is true
set _W to a reference to the first window of P

set _U to a reference to ¬
	(UI elements of P whose ¬
		name of attributes contains "AXSelectedText" and ¬
		value of attribute "AXSelectedText" is not "" and ¬
		class of value of attribute "AXSelectedText" is not class)

tell sys to if (count _U) ≠ 0 then ¬
	return the value of ¬
		attribute "AXSelectedText" of ¬
		_U's contents's first item

set _U to a reference to UI elements of _W

tell sys to repeat while (_U exists)
	tell (a reference to ¬
		(_U whose ¬
			name of attributes contains "AXSelectedText" and ¬
			value of attribute "AXSelectedText" is not "" and ¬
			class of value of attribute "AXSelectedText" is not class)) ¬
		to if (count) ≠ 0 then return the value of ¬
		attribute "AXSelectedText" of its contents's first item
	
	set _U to a reference to (UI elements of _U)
end repeat

"No selection found."