Recaptcha doesn't work with ajax and partial views - asp.net-mvc-4

Question

I'm using Recaptcha in my MVC4 web app. It was working correctly when it was embedded in the form but when I moved the #Html.Raw(Html.GenerateCaptchaHelper()) to partial view and trying to call this partial view via ajax request, it doesn't work!
Extension code :
public static string GenerateCaptchaHelper(this HtmlHelper helper)
{
var captchaControl = new Recaptcha.RecaptchaControl
{
ID = "recaptcha",
Theme = "clean",
PublicKey = ************,
PrivateKey = **********************,
Language = "En"
};
var htmlWriter = new HtmlTextWriter(new StringWriter());
captchaControl.RenderControl(htmlWriter);
return htmlWriter.InnerWriter.ToString();
}
my partial view is has the code like :
<p>#Html.Raw(Html.GenerateCaptchaHelper())</p>
and inside my controller
public PartialViewResult Captcha()
{
return PartialView();
}
and inside my main view:
#using (Html.BeginForm("Login", "Account", new { returnUrl = ViewData["ReturnUrl"] }, FormMethod.Post,null))
{
#Html.AntiForgeryToken()
<form role="form">
<div class="form-group">
<label>#Html.LabelFor(m => m.Email)</label><br />
#Html.TextBoxFor(m => m.Email, null, new { #class = "form-control", autocomplete = "off" })
</div>
<div class="form-group">
<label>#Html.LabelFor(m => m.Password)</label><br />
#Html.PasswordFor(m => m.Password, new { #class = "form-control", autocomplete = "off" })
</div>
<div id="captchaView" class="form-group">
</div>
<button type="submit">Login</button>
</div>
</div>
</form>
}
and the javascript is :
$.ajax({
url: '/Account/Captcha',
type: 'GET',
success: function(data) {
$('#captchaView').html(data);
}
});
Could you please help me to figure out why?