How to recursively search all parentNodes

Question

I want to know, how to find out recursively all parent nodes of an element. Suppose i have following snippet

Hello

Answer 1

You can traverse from an element up to the root looking for the desired tag:

function findUpTag(el, tag) {
    while (el.parentNode) {
        el = el.parentNode;
        if (el.tagName === tag)
            return el;
    }
    return null;
}

You call this method with your start element:

var el = document.getElementById("...");  // start element
var a = findUpTag(el, "A");   // search 
if (a) console.log(a.id);