If you want to check if the email is unique you can use remote rule.
It is from: http://jqueryvalidation.org/remote-method
Example: Makes the email field required, an email and does a remote request to check if the given address is already taken.
$( "#myform" ).validate({
rules: {
email: {
required: true,
email: true,
remote: "check-email.php"
}
}
});
Example: Makes the email field required, an email and does a remote request to check if the given address is already taken. In addition, the http method is set to “post” and the username is sent alongside the email address.
$( "#myform" ).validate({
rules: {
email: {
required: true,
email: true,
remote: {
url: "check-email.php",
type: "post",
data: {
username: function() {
return $( "#username" ).val();
}
}
}
}
}
});