PHP and MySQL for Dynamic Web Sites: Visual QuickPro Guide

Page Caching

Because HTML pages generated by PHP scripts are made on the fly, they frequently should not be cached by Web browsers and proxy servers (caching is a matter of referring to a saved version of a page rather than the original when a URL is requested). However, ISPs often cache popular sites to improve performance, and users sometimes adjust the caching policy of their browsers per their needs (Figure 10.3). As a PHP developer, you can use the header() function to explicitly control caching.

Figure 10.3. Caching settings can be altered in many browsers.

To prevent a page from being cached:

1.	Create a new PHP document (Script 10.3 ...