javascript - Ajax 响应未显示在页面上

Question

我的ajax是

    $.ajax({
        type: 'POST',
        url: ajax.ajax,
        contentType: false,
        processData: false,
        dataType: 'JSON',
        status: 200,
        data: formdata,
        success: function(msg){
            $('#success_message').fadeIn().html(data);
            setTimeout(function() {
                $('#success_message').fadeOut("slow");
        }, 2000 );

        }
    });

这是PHP部分

function form(){ 

    global $wpdb;
    $table = cars;

    foreach ($_FILES as $file) {
        if($file['error'] == UPLOAD_ERR_NO_FILE) {
            continue;
        }

        $valid_ext = array( 'img' , 'png');
        $extension_upload = strtolower(  substr(  strrchr($file['name'], '.')  ,1)  );
        if ( in_array($extension_upload,$valid_ext) ) {
            $name_upload = uniqid() . $file['name'];
            $url_insert = trailingslashit( plugin_dir_path( dirname( __FILE__ ) ) ) . 'uploads';
            wp_mkdir_p($url_insert);
            $name_insert = trailingslashit($url_insert) . $name_upload;
            $action = move_uploaded_file($file['tmp_name'],$name_insert);

            $data = array( 'customer_resume' => $name_upload );
            $format = array( '%s' );

            $success=$wpdb->insert( $table, $data, $format );  
            $msg_true = 'Upload ok ';

        } else {
            $msg_error = 'Upload error';
        }
    }

    $result = !isset($msg_error);
    $msg = array();

    if($result) {
        $msg['error'] = 'true';
        $msg['true'] = $msg_true;
    } else {
        $msg['error'] = 'false';
        $msg['false'] = $msg_error;
    }

    header('Content-Type: application/json');
    echo json_encode($msg);

}

以及我尝试显示成功或错误消息的 HTML

<div id="error_message"></div>
<div id="success_message"></div>

当我单击“提交”按钮时，一切正常并保存在数据库中，但没有指示是否成功。我尝试添加此 msg，但页面上仍然没有显示任何内容。

Answer 1

PHP 端:

您需要打印相同的变量来表示成功和失败:

if($result) {
        $msg['error'] = 'true';
        $msg['msg'] = $msg_true;
    } else {
        $msg['error'] = 'false';
        $msg['msg'] = $msg_error;
    }

JavaScript 端:

AJAX 响应将如下所示

data.error -> true or false.
data.msg -> Success or Error message depending upon program logic.

...
 success: function(data){
  $('#success_message').fadeIn().html(data.msg);
...