停止缓存页面的特定元素

Question

Is they any way to stop caching of a particular element in a page, so that it always loads from the server? I have a div element in the page, which contains some session information that needs to be always updated/retrieved from the server.

My technology here is PHP/jQuery/Joomla.

Does anyone have any idea?

Answer 1

When requesting with xmlhttprequest (ajax) one technique could be is to append a time-stamp value to the URL so each time the function is called the request is unique an example could be

/// javascript get date convert it to milliseconds
 function getDateTime(){ 

     return (new Date().getTime());
 }

so in your ajax GET for example you could do so each request it appends a new time stamp

    req.onreadystatechange=function(){
    .....
    };

    req.open("GET",url+"?ac="+t+"&"+ getDateTime() ,true);
    req.send("");

Now since you using javascript you would beable to only display the "div's conten" only if js is enabled, thus forcing new content each, so embed a inline script and call a function to populate the div

   <script>populateDivsContent()</script>

Answer 2

You can stop cache by using following piece of php code:

//Set no caching
header("Expires: Mon, 26 Jul 1997 05:00:00 GMT");
header("Last-Modified: " . gmdate("D, d M Y H:i:s") . " GMT"); 
header("Cache-Control: no-store, no-cache, must-revalidate"); 
header("Cache-Control: post-check=0, pre-check=0", false);
header("Pragma: no-cache");