php页面每60秒仅刷新div部分

Question

I have a php webpage and this prints html commands and do something else. I have a div section:

<div id="monitor" class="monitoring"><?php include "php/monitoring.php"?></div>

This script in the index.php script should be called every 60 seconds. So I found AJAX and JavaScript useful to do this. Therefore I use this script:

<script type="text/javascript">
window.setInterval(function () {executemonitor()}, 60000);

function executemonitor() {
    $("#monitor").load("php/monitoring.php");
}

The scripts works fine, but the problem is, that second run of the monitoring.php script fails. The script is not able to use the $_SESSION variables. I get the error: Notice: Undefined variable: _SESSION in C:\\xampp\\htdocs\\mi-hand\\php\\monitoring.php on line 168.

If I use the html refresh command, it works.

<meta http-equiv="refresh" content="n" />

But then the whole page is refreshed. I want to avoid this. I want only refreshing the div section, by executing the php script. How can I do this? The monitoring.php file is a separate HTML page.

Answer 1

the _SESSION variable is available in php only after session_start() has been called.

your client calls 2 different scripts :

• index.php which renders the div and includes monitoring.php
• monitoring.php which renders the content of the div

you have a session_start() in index.php but not in monitoring.php so this cannot work when the client calls directly monitoring.php.

You could create a session.php file which does the session initialization (like calling session_start()) and then in both index.php & monitoring.php use

include_once('session.php');

if you have php > 5.4 you could also add in monitoring.php the following code

if (session_status() == PHP_SESSION_NONE) {
  session_start();
}

Source: http://php.net/manual/en/function.session-status.php

Answer 2

如果直接访问"php/monitoring.php" ，则需要在该脚本的开头使用session_start() ，而不仅是在index.php 。