How to Validate Google reCaptcha on Form Submit

Question

If you want to check if the User clicked on the I'm not a robot checkbox, you can use the .getResponse() function provided by the reCaptcha API.

It will return an empty string in case the User did not validate himself, something like this:

if (grecaptcha.getResponse() == ""){
    alert("You can't proceed!");
} else {
    alert("Thank you");
}

In case the User has validated himself, the response will be a very long string.

More about the API can be found on this page: reCaptcha Javascript API