Server echoes warnings/errors that make a json expected response to be invalid

I'm currently writing an ajax form with jquery. The form is handled with a PHP script then the information is sent via the PHPMailer lite class. (http://phpmailer.worxware.com/index.php)

This is the PHP code:

    if ($mail->Send())
        echo '{"message":"Mensaje enviado con éxito","status":"ok"}';
    else
        echo '{"message":"Ocurió un error al envíar el mensaje, intentelo más tarde.","status":"fail"}';

I discovered this problem when the email submitted by the user is not a valid one, resultin开发者_如何学编程g in the following error:

Invalid address: E-mail:Invalid address: E-mail:Could not execute: /usr/sbin/sendmail

I should test the email. Ok. But the problem is that the previous error message "gets in the way" and corrupts the response. So I can solve the email error, but any other warning/error would corrupt the response.

A 'corrupted' response example:

Invalid address: E-mail:Invalid address: E-mail:Could not execute: /usr/sbin/sendmail {"message":"Ocurió un error al envíar el mensaje, intentelo más tarde.","status":"fail"}

(First line should not be there)

And this is the javascript (jquery) part:

        $.ajax
    ({
        type: "POST",
        url: "contact.php",
        data: $(this).serialize(),
        success: function(data)
        {
            if(data.status == 'fail')
            {
                do something with data.message;
            }
            else if(data.status == 'ok')
            {
                do something else with data.message;
            }
        },
        dataType: 'json'
    });

Any help with this? :) thank you

Its a long shot but have you tried

@ if ($mail->Send())

The @ suppresses php errors on a given line of code.