How to find the nearest common ancestors of two or more nodes?

Question

Users selects two or more elements in a HTML page. What i want to accomplish is to find those elements\' common ancestors (so body node would be the common ancestor if none

Answer 1

This doesn't require much code anymore to solve:

steps:

1. grab parent of node_a
2. if parent of node_a contains node_b return parent (in our code, the parent is referenced as node_a)
3. if parent does not contain node_b we need to keep going up the chain
4. end return null

code:

function getLowestCommonParent(node_a, node_b) {
    while (node_a = node_a.parentElement) {
        if (node_a.contains(node_b)) {
            return node_a;
        }
    }

    return null;
}