function swapNodes(a, b) {
    if(a == null || b == null){
      return false;
    }
    else {
        var aParent = a.parentNode;
        var aSibling = (a.nextSibling === b) ? a : a.nextSibling;
        console.log(a);
        console.log(b);
        b.parentNode.insertBefore(a, b);
        aParent.insertBefore(b, aSibling);
    }
  }