offset = document.getElementsByClassName('active')[0].offsetTop;
height = document.getElementById('tree').clientHeight;
if (offset > (height * .7)) {
tree.scrollTop = offset - height * .3;
}
offset = document.getElementsByClassName('active')[0].offsetTop;
height = document.getElementById('tree').clientHeight;
if (offset > (height * .7)) {
tree.scrollTop = offset - height * .3;
}