function toggle(element) {
    //var imgNode = element.firstChild;
    var childrenLevel1 = element.parentNode.getElementsByTagName('div');

    for (var i = 0; i < childrenLevel1.length; i++) {
        if (childrenLevel1.item(i).style.display == 'none') {
            //imgNode.src = 'images/tree-open.gif';
            childrenLevel1.item(i).style.display = 'block';
        } else {
            //imgNode.src = 'images/tree-closed.gif';
            childrenLevel1.item(i).style.display = 'none';
        }
    }
}