apple script file path

gistfile1.txt

set filePath to ""
tell application "QuickTime Player"
	try
		if file path of front document is not equal to missing value then
			set filePath to file path of front document
		end if
	end try
	try
		if path of front document is not equal to missing value then
			set filePath to path of front document
		end if
	end try
	try
		if file of front document is not equal to missing value then
			set filePath to file of front document
		end if
	end try
end tell

return (alias filePath)'s POSIX path