Location.hash Does Not Work Without SetTimeout

Basically, my problem is exactly as described in the subject. The
problem is somewhat intermittent and unpredictable, but the majority
of the time if I just have a statement such as

window.onload=location.hash('somewhere');

the URL is indeed appended, i.e. www.example.com/index.php#somewhere,
but window itself doesn't actually move to the bookmark. However, if
I do something like

window.onload=setTimeout("location.hash('somewhere')",0)

it works fine. On very large pages, the timeout actually has to be a
second or two. Any idea why this is happening? I don't know much
about JS, but my thought is that it's trying to move to that bookmark
before it has actually been loaded in the page; the timeout forces it
to wait for the rest of the page to load before going to the bookmark.