tell application "iTunes"
-- Uncomment the following line if you want to create a global hotkey (available in any app)
-- activate
set winname to name of browser window 1
-- Uncomment the following line if you want to switch to your music library first (else this hotkey starts a search in the current library, i.e. Music, Apps, iTunes Store etc.)
-- set view of window winname to playlist "Music"
end tell
tell application "System Events"
tell application process "iTunes"
set (value of text field 1 of window winname) to ""
set focused of text field 1 of window winname to true
end tell
end tell