javascript Getting distance of child element from top-left corner of Parent element

Is there a way to get the offset of a ChildElement from a given parent element?

for example if a DIV in contained within a parent DIV with id "xyz"

is there a 开发者_开发知识库way to say

parent = $("xyz");
child = $("abc");

child.offset(parent);

Thank you

A convenient method is Element.getPositionedOffset(), but only when the parent element has a position style property.

var offset = $('abc').positionedOffset();
offset.left;
offset.top;

Otherwise it takes a little more work:

var parent = $('xyz',
    child = $('abc'),
    offset = child.viewportOffset().relativeTo(parent.viewportOffset());

The advantage here is the two elements need not be directly related, any pair of elements on the page can do.