This usually means that the user mixed up our lowercase/uppercase naming convention; see https://github.com/facebook/react/pull/3429#issuecomment-85166440.

We could add a message like

> Warning: The tag <commentBox> is unrecognized in this browser. If you meant to render a React component, start its name with an uppercase letter.

We'd check this only once per tag and only in development mode.

}
var mediaEvents = {
  topAbort: 'abort',
  topCanPlay: 'canplay',
  topCanPlayThrough: 'canplaythrough',
  topDurationChange: 'durationchange',
  topEmptied: 'emptied',
  topEncrypted: 'encrypted',
  topEnded: 'ended',
  topError: 'error',
  topLoadedData: 'loadeddata',
  topLoadedMetadata: 'loadedmetadata',
  topLoadStart: 'loadstart',
  topPause: 'pause',
  topPlay: 'play',
  topPlaying: 'playing',
  topProgress: 'progress',
  topRateChange: 'ratechange',
  topSeeked: 'seeked',
  topSeeking: 'seeking',
  topStalled: 'stalled',
  topSuspend: 'suspend',
  topTimeUpdate: 'timeupdate',
  topVolumeChange: 'volumechange',
  topWaiting: 'waiting',
};
function trackInputValue() {
  inputValueTracking.track(this);
}
function trapClickOnNonInteractiveElement() {