function showOnly(showId, parentId, tagName) {
                var parObj = document.getElementById(parentId);
                var tagType = "DIV";
                if (tagName) {
                    tagType = tagName.toUpperCase();
                }
                if (parObj) {
                    var children = parObj.childNodes;
                    // alert(db_DumpTree(children, ''));
                    for(c = 0; c < children.length; c++) {
                        if (children[c].nodeName == tagType ) {
                            if (children[c].id == showId) {
                                children[c].style.display = 'block';
                            } else {
                                children[c].style.display = 'none';
                            }
                        }
                    }
                }
            }