Run the [`fixtures/ssr` test harness](https://github.com/facebook/react/tree/master/fixtures/ssr). In the terminal, the following warning is logged:

```
Warning: Unknown prop `onClick` on <a> tag. Remove this prop from the element. For details, see https://fb.me/react-unknown-prop
  in a (at Page.js:12)
  in p (at Page.js:18)
  in div (at Page.js:17)
  in Page (at App.js:12)
  in div (at App.js:10)
  in body (at Chrome.js:17)
  in html (at Chrome.js:9)
  in Chrome (at App.js:9)
  in App (at render.js:18)
```

SSR behavior should match client-side behavior and not warn for a valid attribute.
if (type.indexOf('-') >= 0 || props.is) {
    return;
  }
  warnUnknownProperties(type, props, debugID);
}
var ReactDOMUnknownPropertyHook = {
  
  validateProperties,
  
  onBeforeMountComponent(debugID, element) {
    if (__DEV__ && element != null && typeof element.type === 'string') {
      validateProperties(element.type, element.props, debugID);
    }
  },
  onBeforeUpdateComponent(debugID, element) {
    if (__DEV__ && element != null && typeof element.type === 'string') {
      validateProperties(element.type, element.props, debugID);
    }
  },
};
module.exports = ReactDOMUnknownPropertyHook;