function showLogin(){
// document.getElementById('login').style.display=(document.getElementById('login').style.display != 'block' ? 'block' : 'none');
       var agt = navigator.userAgent.toLowerCase();
       var is_bsd   = (agt.indexOf("bsd") != -1);
       var is_x11   = (agt.indexOf("x11") != -1);
       var is_linux = (agt.indexOf("linux") != -1);
       var is_mac   = (agt.indexOf("mac") != -1);
       obj = document.getElementById('login').style;
       if ( is_bsd || is_x11 || is_linux || is_mac ) {
             obj.top = '20px';
       }
       obj.display = (obj.display != 'block' ? 'block' : 'none');
}


function OpenAnsw(ans_id) {
    var obj_ctrl = getObj(ans_id);
    if ( obj_ctrl ) {
      obj_ctrl.style.display = (obj_ctrl.style.display == "none" ? "block" : "none");

    }
  }
  
  function getObj(obj_name, doc_obj) { //get DOM node
    if (!doc_obj) doc_obj = document;
    if (doc_obj.all)
        return doc_obj.all[obj_name];
    else if (doc_obj.getElementById)
        return doc_obj.getElementById(obj_name);
    return null;
}