function $(id) {
  if      (document.layers)         return document.layers[id];         // NC 4
  else if (document.all)            return document.all[id];            // IE 4
  else if (document.getElementById) return document.getElementById(id); // DOM
  else                              return null;        
}

function chBigImg(pic){
  var a=$('imgb');
  if (a!=null) a.src='./catalog/'+pic;
}

function wo(url, width, height) {
  var a='www'+Math.round(Math.random()*1000000);
  var www = window.open(url, a, 'resizable=yes,scrollbars=yes,menubar=no,left='+(screen.width/2-width/2)+',top='+(screen.height/2-height/2)+',width='+width+',height='+height);
  www.focus();
};