Validate Google Recaptcha with Java Script before sending PHP

How do you make the user have to click on the recaptcha? Of course there are many examples where you can solve this in the php-form, but I am looking for a java script solution which avoids unnecessary server traffic. Does anybody have an idea how to solve this?Thank You very much! -- You received this message because you are subscribed to the Google Groups "reCAPTCHA" group. To unsubscribe from this group and stop receiving emails from it, send an email to recaptcha+unsubscribe@googlegroups.com. To post to this group, send email to recaptcha@googlegroups.com. Visit this group at http://bit.ly/1dkFnYd. For more options, visit http://bit.ly/P65DvS.