Testing objects for ancestor/descendent relationship in JavaScript or Jquery

Question

I\'m trying to come up with a reusable JS or jQuery function that would allow me to test if one object is a DOM descendant of another.

I\'ve seen a model of testing

Answer 1

a.contains(b)

This is a pure JavaScript solution using Node.contains. The function is inclusive, a.contains(a) evaluates to true.

There's an edge case in IE9: if b is a text node, contains will always return false.