How to find the first common XPath ancestor in Javascript?

Question

I have two XPath, for example:

  / html / body / div [3] / div [4] / table / tbody / tr [2] / td [4] and
 / html / body / div [3] / div [4] / table / tbody / tr [2] / td [3] / a [2]

How can I find the first common ancestor now? In this case, it will be /html/body/div[3]/div[4]/table/tbody/tr[2]/ .

I found this question , but the solution is in ruby ​​and actually does not let me understand how to do this in Javascript. Can anybody help me? Thanks.

Answer 1

This is similar to JS and not XSLT, although XPATHs elements are a common factor.