repeat
set my_number to text returned of (display dialog "Please enter some number..." default answer "123" with title "Request" buttons {"Cancel", "OK"} default button 2 with icon 1)
if my_number ≠"" then
try
set my_number to my_number as number
--get the absolute value
if my_number is less than 0 then
set my_number to -my_number
end if
exit repeat
end try
end if
end repeat
do shell script "/usr/bin/curl " & quoted form of ("http://www.zzz.com.php?var=" & my_number)