Depends - children's shoe sizes go up to 13 then start at 1 again, though dot should be able to give you fuller advice when she sees this as it's one of her fields of expertise.
Kids sizes go from 0 to 13, then it starts at adult sizes which is 3 onwards, so an adult size 5 is wayyyyy bigger than a toddler 5. At a guess I would say that a 'junior' size 5 would really mean a toddler size 5.
least I think that's correct, though I could be wrong, I often am!
If the answer is no, they are the same, then you can buy your trainers/similiar in the childrens' dept (like I do size 4�) and pay less money than you would in the adult section!!!