提交mailchimp subscribe php后我有一个空白页面

I use bellow html code to submit user email in my mailchimp account list using mailchimp API.

Form Code:

    .....

    <form id="signup-form" action="php/newsletter-subscribe.php" method="post">
        <input type="email" name="email" id="email" placeholder="Email Address" />
        <br>
        <input type="submit" value="Go!" onclick="wating()" />
    </form>

    ......

newsletter-subscribe PHP code:

require_once 'mailchimp/MailChimp.php';
use \DrewM\MailChimp\MailChimp;

// Email address verification
function isEmail($email) {
    return filter_var($email, FILTER_VALIDATE_EMAIL);
}

if($_POST) {
    $mailchimp_api_key = 'xxxxxxxxxxxxxxxxxxxxx-xx'; // enter your MailChimp API Key
    $mailchimp_list_id = 'xxxxxxxxxx'; // enter your MailChimp List ID

    $subscriber_email = addslashes( trim( $_POST['email'] ) );
    if( !isEmail($subscriber_email) ) {
        echo '<script type="text/javascript">swal("Error!", "Please try again.", "error")</script>';
    } else {
        $array = array();
        $MailChimp = new MailChimp($mailchimp_api_key);
        $result = $MailChimp->post("lists/$mailchimp_list_id/members", [
            'email_address' => $subscriber_email,
            'status'        => 'subscribed',
        ]);

        if($result == false) {
            $array = '<script type="text/javascript">swal("Error!", "Please try again.", "error")</script>';
        } else {
            $array = '<script type="text/javascript">swal("Great!", "Your email has been subscribed", "success")</script>';
        }
        echo json_encode($array);
    }
}

The problem is after i submit the form i get blank page without any error log and the email added to my mailchimp account without any error.

I try to change the echo javascript in line 22, 35 and 38 with another java script alert like alert("Text Here"); and it's work except i get the same thing blank page

How to solve this problem and echo the javascript alert in the same html form page without redirect to blank page?

First you are setting:

$array = array();

However later, you do:

    if($result == false) {
        $array = '<script type="text/javascript">swal("Error!", "Please try again.", "error")</script>';
    } else {
        $array = '<script type="text/javascript">swal("Great!", "Your email has been subscribed", "success")</script>';
    }
    echo json_encode($array);

In other words, you are changing array to a string. Try to change the code to:

    if($result == false) {
        $array = array('<script type="text/javascript">swal("Error!", "Please try again.", "error")</script>');
    } else {
        $array = array('<script type="text/javascript">swal("Great!", "Your email has been subscribed", "success")</script>');
    }
    echo json_encode($array);

Also, I would avoid using <script type="text/javascript"> there and I would just return a proper json response. Then, you call this file with ajax (jquery), decode the json and show the alert.

Perhaps something like this will give you an idea: http://labs.jonsuh.com/jquery-ajax-php-json/