Page Cache

dspeer

How can I keep my page from being cached by the user's browser? I am using a web front end to a real-time business process and in testing, caching has caused some issues. Any help?

stolzyboy

quick yahoo search yielded this:

For Navigator and IE browsers, add <HTTP-EQUIV="PRAGMA" CONTENT="NO-CACHE"> in the HEAD section of the HTML . For IE, and if your whole page is < 64KB, ALSO add a HEAD section to the END of the HTML page like this.

<HTML>
<HEAD>
<META HTTP-EQUIV="REFRESH" CONTENT="5">
<TITLE> blah blah blah </TITLE>
</HEAD>
<BODY>
This is an example of where to place the second header section
so that the "Pragama, No-Cache" metatag will work as it is supposed to.

</BODY>
<HEAD>

</HEAD>

</HTML>

dspeer

Gracias!

jpmoriarty

i've used the above code, but i think the page is being cached by my local networks ISA server - is there any html that i can use that will stop that, or do i have to tell the site not to cache at server level?

stolzyboy

i don't think there is anything you can do if it is caching at server level, i may be wrong, but that sounds like a job for admins on the specific servers and maybe isp (good luck on this one) 🙂

jpmoriarty

thanks for the assistance - with a little help from more google searches I got it to go in the end.

The pragma line above needs the following after it to work on IE > 5.0:

<META HTTP-EQUIV="Expires" CONTENT="-1">

but i also used the following php headers to really make sure that it wasnt cached!:

	header("Expires: Mon, 26 Jul 1997 05:00:00 GMT"); 
	header("cache-Control: no-store, no-cache, must-revalidate");
	header("cache-Control: post-check=0, pre-check=0", false);
	header("Pragma: no-cache");

overkill? possibly, but it's got the job done!