将reCaptcha ajax api实现为已使用ajax的现有Web表单

Question

I have a signup form on my home page which uses server side validation and ajax so my page doesn't refresh while validating.

When all validation is passed my page is taken to a registered.html which is a temporary page for now. Later on it will be an account area.

What I want

I want to have 1 last step after the actual form validation which will be my reCaptcha validation. Instead of submitting the form after validation I want reCaptcha to popup twitter style or just replace the form fields facebook style.

Only after successful captcha validation will the form be submitted. I have provided the code below and would really appreciate if someone could advise me on the best way to implement this. Right now I'm at a stage where I'm confused.

Error checking and at the very bottom you can see the echo statement that sends a user to registered.html after successful validation

<?php

// we check if everything is filled in

if(empty($_POST['first_name']) || empty($_POST['last_name']) || empty($_POST['email']) || empty($_POST['password']))
{
 die(msg(0,"All the fields are required"));
}


// is the sex selected?

if(!(int)$_POST['sex'])
{
 die(msg(0,"You have to select your sex"));
}


// is the birthday selected?

if(!(int)$_POST['day'] || !(int)$_POST['month'] || !(int)$_POST['year'])
{
 die(msg(0,"You have to fill in your birthday"));
}


// is the email valid?

if(!(preg_match("/^[\.A-z0-9_\-\+]+[@][A-z0-9_\-]+([.][A-z0-9_\-]+)+[A-z]{1,4}$/", $_POST['email'])))
 die(msg(0,"You haven't provided a valid email"));



// Here I must put your code for validating and escaping all the input data,
// inserting new records in your DB and echo-ing a message of the type:

// echo msg(1,"/member-area.php");

// where member-area.php is the address on my site where registered users are
// redirected after registration.




echo msg(1,"registered.html");


function msg($status,$txt)
{
 return '{"status":'.$status.',"txt":"'.$txt.'"}';
}
?>

The javascript

$(document).ready(function () {

    $('#fhjoinForm').submit(function (e) {

        register();
        e.preventDefault();

    });

});


function register() {
    hideshow('loading', 1);
    error(0);

    $.ajax({
        type: "POST",
        url: "submit.php",
        data: $('#fhjoinForm').serialize(),
        dataType: "json",
        success: function (msg) {

            if (parseInt(msg.status) == 1) {
                window.location = msg.txt;
            } else if (parseInt(msg.status) == 0) {
                error(1, msg.txt);
            }

            hideshow('loading', 0);
        }
    });

}


function hideshow(el, act) {
    if (act) $('#' + el).css('visibility', 'visible');
    else $('#' + el).css('visibility', 'hidden');
}

function error(act, txt) {
    hideshow('error', act);
    if (txt) $('#error').html(txt);
}   

Now I'm thinking there must be a simple way to implement reCaptcha ajax api into my current form. At first I tried to add onclick="showRecaptcha('recaptcha_div');" to the end of my form where my input type=submit is located this didn't work.

The end of my form

    <td><input type="submit" class="joinButton" value="Join Us" /><img id="loading" src="<?php echo base_url()?>images/join/ajax-loader.gif" alt="working.." /></td>
    <div id="recaptcha_div"></div>
    </tr>

I've follows the instructions on the recaptcha website and no luck so far. Code snippets, advice anything will help. I appreciate it.

Thanks