var _POPUP_FEATURES = 'location=0,statusbar=0,menubar=0,width=500,height=600';

function isUndefined(a) { return typeof a == 'undefined' }

function raw_popup(url, target, features) {
  if (isUndefined(features)) {
    features = _POPUP_FEATURES;
  }
  if (isUndefined(target)) {
    target = '_blank';
  }
  var theWindow =
    window.open(url, target, features);
  theWindow.focus();
  return theWindow;
}

function link_popup(src, features) {
  return raw_popup(src.getAttribute('href'),src.getAttribute('target') || '_blank',features);
}