you have to get the DOM element from jQuery Object
$scrollHolder[0].scrollTop = $scrollHolder[0].scrollHeight;
or
$scrollHolder.get(0).scrollTop = $scrollHolder.get(0).scrollHeight;
$('#element');
is jQuery Object. It creates an array of matched Objects . But here you have id-selector so you only get one Object you can refer to the Native DOM object by using array index [index]
or using .get(index)
.
document.getElementById("element");
is a native DOM Object
FYI
jQuery way of doing it.
$scrollHolder.scrollTop($scrollHolder.prop('scrollHeight'));