set {y1, x1, y2, x2} to {100, 100, 400, 400} -- area for selection
tell application "Adobe InDesign CS5"
tell page 1 of document 1
select (every page item where ¬
((item 1 of its geometric bounds < y2 and item 1 of its geometric bounds > y1) ¬
or (item 3 of its geometric bounds > y1 and item 3 of its geometric bounds < y2)) ¬
and ¬
((item 2 of its geometric bounds < x2 and item 2 of its geometric bounds > x1) ¬
or (item 4 of its geometric bounds > x1 and item 4 of its geometric bounds < x2)) ¬
)
end tell
end tell