function toggle_all_items (stat) {
var ul  =  document.getElementById('root').getElementsByTagName('ul');
var img =  document.getElementById('root').getElementsByTagName('img');
for (var i = 0; i < ul.length; i++) {
ul[i].className =  stat? "opened" : "closed";
}
for (var j = 0; j < img.length; j++) {
if (img[j].src.indexOf("opened.gif") == -1 && img[j].src.indexOf("closed.gif") == -1) continue;
img[j].src =  stat? "opened.gif" : "closed.gif";
}
}