[jQuery] Selectors only matching first element

[jQuery] Selectors only matching first element


Hi all, I need some help here. I'm still pretty new to jQuery and
Javascript in general, so apologies if this is a basic question.
All I am trying to do is a simple "select all" checkbox script. The
problem is, no matter what I seem to do, only the first element is
matched.
$("input:checkbox").attr("checked", true);
checks the first box only.
Same with:
$("input:checkbox").each(...
I even tried copying this script directly from the jQuery
documentation page:
$("div").css("border","9px solid red");
It applies a red border to the first div on my page.. the example in
the documentation applies it to all divs.
What could be going on here?
Thanks.