It simply mean
$get("Accordion1")
is null (not an object). If this is jQuery, the syntax is wrong, could be:
jQuery.get
,
$.get
or
$.ajax
. Please see:
http://api.jquery.com/jQuery.get/[
^].
If this is something else, I'm not sure. You did not tag jQuery, so it can by nearly anything. For example "Accordion1" might not be in request, check up spelling. By they way, using such identifiers ("something1", "something2") is really bad; the artifact of Designer; it should be something semantic.
—SA