diff --git a/web/app/controllers/image_hosting/index.php b/web/app/controllers/image_hosting/index.php
index 4e45f2e..2237a86 100644
--- a/web/app/controllers/image_hosting/index.php
+++ b/web/app/controllers/image_hosting/index.php
@@ -19,13 +19,11 @@
 	$count = $_result["count(*)"];
 
 	function throwError($msg) {
-		die(json_encode(['status' => 'error', 'message' => $msg]));
+		returnJSONData(['status' => 'error', 'message' => $msg]);
 	}
 
 	$allowedTypes = [IMAGETYPE_PNG, IMAGETYPE_JPEG];
 	if ($_POST['image_upload_file_submit'] == 'submit') {
-		header('Content-Type: application/json');
-
 		if (!crsf_check()) {
 			throwError('expired');
 		}
@@ -68,7 +66,7 @@
 		$existing_image = DB::selectFirst("SELECT * FROM users_images WHERE `hash` = '$hash'");
 
 		if ($existing_image) {
-			die(json_encode(['status' => 'success', 'path' => $existing_image['path']]));
+			returnJSONData(['status' => 'success', 'path' => $existing_image['path']]);
 		}
 
 		$image = new Imagick($_FILES["image_upload_file"]["tmp_name"]);
@@ -94,7 +92,7 @@
 
 		DB::insert("INSERT INTO users_images (`path`, uploader, width, height, upload_time, size, `hash`) VALUES ('$filename', '{$myUser['username']}', $width, $height, now(), {$_FILES["image_upload_file"]["size"]}, '$hash')");
 
-		die(json_encode(['status' => 'success', 'path' => $filename]));
+		returnJSONData(['status' => 'success', 'path' => $filename]);
 	} elseif ($_POST['image_delete_submit'] == 'submit') {
 		crsf_defend();
 
diff --git a/web/app/controllers/super_manage.php b/web/app/controllers/super_manage.php
index 45911c8..59687b1 100644
--- a/web/app/controllers/super_manage.php
+++ b/web/app/controllers/super_manage.php
@@ -315,8 +315,7 @@
 	
 			DB::query("insert into user_info (username, realname, email, school, password, svn_password, register_time, usergroup) values ('$username', '$realname', '$email', '$school', '$password', '$svn_password', now(), 'U')");
 			
-			header('Content-Type: application/json');
-			die(json_encode(['status' => 'success', 'message' => '']));
+			returnJSONData(['status' => 'success', 'message' => '']);
 		};
 		$register_form->setAjaxSubmit(<<<EOD
 		function(res) {
@@ -371,8 +370,7 @@ EOD);
 
 			DB::query("update user_info set password = '$esc_password' where username = '$esc_username'");
 
-			header('Content-Type: application/json');
-			die(json_encode(['status' => 'success', 'message' => '用户 ' . $vdata['username'] . ' 的密码已经被成功重置。']));
+			returnJSONData(['status' => 'success', 'message' => '用户 ' . $vdata['username'] . ' 的密码已经被成功重置。']);
 		};
 		$change_password_form->submit_button_config['margin_class'] = 'mt-3';
 		$change_password_form->submit_button_config['text'] = '重置';
@@ -438,8 +436,7 @@ EOD);
 					break;
 			}
 
-			header('Content-Type: application/json');
-			die(json_encode(['status' => 'success', 'message' => '用户 ' . $username . ' 现在是 ' . $usergroup . '。']));
+			returnJSONData(['status' => 'success', 'message' => '用户 ' . $username . ' 现在是 ' . $usergroup . '。']);
 		};
 		$change_usergroup_form->setAjaxSubmit(<<<EOD
 		function(res) {
diff --git a/web/app/controllers/user_info_edit.php b/web/app/controllers/user_info_edit.php
index bdbf480..bd213cc 100644
--- a/web/app/controllers/user_info_edit.php
+++ b/web/app/controllers/user_info_edit.php
@@ -179,8 +179,7 @@ EOD);
 
 			DB::update("UPDATE user_info SET email = '$esc_email', qq = '$esc_qq', sex = '$esc_sex', motto = '$esc_motto', codeforces_handle = '$esc_codeforces_handle', github = '$esc_github', website = '$esc_website', avatar_source = '$esc_avatar_source' WHERE username = '{$user['username']}'");
 
-			header('Content-Type: application/json');
-			die(json_encode(['status' => 'success']));
+			returnJSONData(['status' => 'success']);
 		};
 		$update_profile_form->submit_button_config['margin_class'] = 'mt-3';
 		$update_profile_form->submit_button_config['text'] = '更新';
@@ -206,31 +205,28 @@ EOD);
 		$update_profile_form->runAtServer();
 	} elseif ($cur_tab == 'password') {
 		if (isset($_POST['submit-change_password']) && $_POST['submit-change_password'] == 'change_password') {
-			header('Content-Type: application/json');
-
 			$old_password = $_POST['current_password'];
 			$new_password = $_POST['new_password'];
 
 			if (!validatePassword($old_password) || !checkPassword($user, $old_password)) {
-				die(json_encode(['status' => 'error', 'message' => '旧密码错误']));
+				returnJSONData(['status' => 'error', 'message' => '旧密码错误']);
 			}
 
 			if (!validatePassword($new_password)) {
-				die(json_encode(['status' => 'error', 'message' => '新密码不合法']));
+				returnJSONData(['status' => 'error', 'message' => '新密码不合法']);
 			}
 
 			if ($old_password == $new_password) {
-				die(json_encode(['status' => 'error', 'message' => '新密码不能与旧密码相同']));
+				returnJSONData(['status' => 'error', 'message' => '新密码不能与旧密码相同']);
 			}
 
 			$password = getPasswordToStore($new_password, $user['username']);
 			DB::update("UPDATE `user_info` SET `password` = '$password' where `username` = '{$user['username']}'");
-			die(json_encode(['status' => 'success', 'message' => '密码修改成功']));
+
+			returnJSONData(['status' => 'success', 'message' => '密码修改成功']);
 		}
 	} elseif ($cur_tab == 'privilege') {
 		if (isset($_POST['submit-privilege']) && $_POST['submit-privilege'] == 'privilege' && isSuperUser($myUser)) {
-			header('Content-Type: application/json');
-
 			$user['usertype'] = 'student';
 
 			if ($_POST['user_type'] == 'teacher') {
@@ -258,7 +254,7 @@ EOD);
 
 			DB::update("UPDATE `user_info` SET `usertype` = '{$user['usertype']}' where `username` = '{$user['username']}'");
 
-			die(json_encode(['status' => 'success', 'message' => '权限修改成功']));
+			returnJSONData(['status' => 'success', 'message' => '权限修改成功']);
 		}
 	}
 
diff --git a/web/app/libs/uoj-form-lib.php b/web/app/libs/uoj-form-lib.php
index 18560c2..f91aae2 100644
--- a/web/app/libs/uoj-form-lib.php
+++ b/web/app/libs/uoj-form-lib.php
@@ -861,4 +861,9 @@ EOD;
 		};
 		return $form;
 	}
+
+	function returnJSONData($data) {
+		header('Content-Type: application/json');
+		die(json_encode($data));
+	}
 	?>