Update README.md

Author: MatthieuJnon

README.md

@@ -118,7 +118,7 @@ set to `true` if you don't want to see the launcher.
 | `customMessageDelay`   | See below          | This prop is a function, the function take a message string as an argument. The defined function will be called everytime a message is received and the returned value will be used as a milliseconds delay before displaying a new message.                                                                                                                                                                                                                                                                                 |
 | `params`               | See below          | Essentially used to customize the image size, also used to change storage options.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                |
 | `storage`              | `"local"`          | ⚠️ This is not a prop, it has to be passed inside the params object above. <br> Specifies the storage location of the conversation state in the browser. `"session"` defines the state to be stored in the session storage. The session storage persists on reload of the page, and is cleared after the browser or tab is closed, or when `sessionStorage.clear()`is called. `"local"` defines the state to be stored in the local stoage. The local storage persists after the the browser is closed, and is cleared when the cookies of the browser are cleared, or when `localStorage.clear()`is called. |
-| `customComponent`      | `null`             | Custom component to be used with custom responses. E.g.: `customComponent={ (messageData) => (<div>Custom React component</div>)` }|
+| `customComponent`      | `null`             | Custom component to be used with custom responses. E.g.: `customComponent={ (messageData) => (<div>Custom React component</div>)}`. Please note that this can only be used if you call the webchat from a React application as you can't write a component in pure Javscript. |
 | `onWidgetEvent`        | `{}`             | call custom code on a specific widget event ( `onChatOpen`, `onChatClose`, `onChatHidden`, are available for now ), add a function to the desired object property in the props to have it react to the event. |
 
 ### Additional Examples