Set 2nd param to this.childNodes[1].id

Rather than a hardcoded string which we need to update later, make it
relate to the inner node items ID
onclick needs if check and simpler title updating

onclick function needed is statement plus passing of event on anon
function to solve repeated CTRL+click issue
Update title not by adjusting hardcoded values but by looking to ID of
targetElem
We're able to get rid of a lot of code here as the onmouseover function
is now looking to a child node item in get-branch.php, so no need to
mess with updating hardcoded string values.