Funzionamento dello snippet WebSignup

$modx->invokeEvent("OnWebSaveUser",
array(
"mode" => "new",
"userid" => $key,
"username" => $username,
"userpassword" => $password,
"useremail" => $email,
"userfullname" => $fullname
));

<!-- #declare:separator <hr> --> 
<!-- login form section-->
<!--INIZIO CODICE MODIFICATO -->
<form method="post" name="websignupfrm" id="websignupfrm" action="[+action+]">
<!--FINE CODICE MODIFICATO-->
<fieldset>
<h3>User Details</h3>
...
<h3>Bot-Patrol</h3>
<p>Enter the word/number combination shown in the image below.</p>
<label>Form code:* 
<input type="text" name="formcode" class="inputBox" size="20" /></label>
<a href="[+action+]"><img align="top" src="manager/includes/veriword.php" width="148" height="60" alt="If you have trouble reading the code, click on the code itself to generate a new random code." style="border: 1px solid #039" /></a>
</fieldset>
<!--INIZIO CODICE AGGIUNTO -->
<label for="disclaimer">Privacy Statement<br /><textarea name="disclaimer" cols="60" rows="6">Testo privacy</textarea></label><br />
<label for="agree"><input type="checkbox" id="agree" name="agree" value="agree" />I agree</label><br />
<!--FINE CODICE AGGIUNTO -->
<fieldset>
<input type="submit" value="Submit" name="cmdwebsignup" />
</fieldset>
</form>
<script language="javascript" type="text/javascript"> 
var id = "[+country+]";
var f = document.websignupfrm;
var i = parseInt(id);	
if (!isNaN(i)) f.country.options[i].selected = true;
<!--INIZIO CODICE AGGIUNTO -->
document.getElementById("websignupfrm").onsubmit = function() {
if (!document.getElementById("agree").checked) {
alert("You must agree to the privacy statement to proceed");
return false;
}
return true;
}
<!--FINE CODICE AGGIUNTO -->
</script>
...