function filterLeaks (ok, globals) {
  return globals.filter(function (key) {
    // Firefox and Chrome exposes iframes as index inside the window object
    if (/^\d+/.test(key)) {
      return false;
    }

    // in firefox
    // if runner runs in an iframe, this iframe's window.getInterface method
    // not init at first it is assigned in some seconds
    if (global.navigator && (/^getInterface/).test(key)) {
      return false;
    }

    // an iframe could be approached by window[iframeIndex]
    // in ie6,7,8 and opera, iframeIndex is enumerable, this could cause leak
    if (global.navigator && (/^\d+/).test(key)) {
      return false;
    }

    // Opera and IE expose global variables for HTML element IDs (issue #243)
    if (/^mocha-/.test(key)) {
      return false;
    }

    var matched = ok.filter(function (ok) {
      if (~ok.indexOf('*')) {
        return key.indexOf(ok.split('*')[0]) === 0;
      }
      return key === ok;
    });
    return !matched.length && (!global.navigator || key !== 'onerror');
  });
}
Filter leaks with the given globals flagged as `ok`.

@api private
@param {Array} ok
@param {Array} globals
@return {Array}