If you've ever written a large-scale PHP application you've probably seen how cumbersome it can be having PHP and HTML all mixed up in one file -- and it gets even worse when you have to update your design. This is what template-engines are here for. Template-engines separate programming logic and design, which results in better readability for both your PHP and HTML code. This in turn makes our lives as developers easier.
When I started my search for a template engine that I could use in my applications, I was looking for these features:
Easy to use
Easy to learn
Visible in different browsers
The template-engine I ultimately ended up choosing was patTemplate, which was developed and created by Stephan Schmidt. You can download it for free from http://www.php-tools.de and I recommend that download it before you continue before you continue reading.