[added] temporary solution to the lang issue

- Letting configure the language from an external global variable
- Updated the readme with the instructions to set the language

fixes #17

Author: iranreyes

README.md

@@ -39,7 +39,7 @@ render(
       ref="recaptcha"
       sitekey="Your client site key"
       onChange={onChange}
-    />, 
+    />,
     document.body
 );
 ```
@@ -58,6 +58,14 @@ Other properties can be used to customised the rendering.
 | onExpired | func | *optional* callback when the challenge is expired and has to be redone by user. By default it will call the onChange with null to signify expired callback. |
 | stoken | string | *optional* set the stoken parameter, which allows the captcha to be used from different domains, see [reCAPTCHA secure-token] |
 
+In order to translate the reCaptcha widget you should create a global variable configuring the desire language, if you don't provide it reCaptcha will pick up the user's interface language.
+
+```
+window.recaptchaOptions = {
+  lang: 'fr'
+}
+```
+
 ## Component API
 
 The component also has some utility functions that can be called.
@@ -86,7 +94,7 @@ render(
       sitekey="Your client site key"
       onChange={onChange}
       grecaptcha={grecaptchaObject}
-    />, 
+    />,
     document.body
 );
 ```

src/recaptcha-wrapper.js

@@ -2,7 +2,10 @@ import ReCAPTCHA from "./recaptcha";
 import makeAsyncScriptLoader from "react-async-script";
 
 const callbackName = "onloadcallback";
-const URL = `https://www.google.com/recaptcha/api.js?onload=${callbackName}&render=explicit`;
+const lang = typeof window !== "undefined" && (window.recaptchaOptions && window.recaptchaOptions.lang) ?
+  "&hl=" + window.recaptchaOptions.lang :
+	"";
+const URL = `https://www.google.com/recaptcha/api.js?onload=${callbackName}&render=explicit${lang}`;
 const globalName = "grecaptcha";
 
 export default makeAsyncScriptLoader(ReCAPTCHA, URL, {