I have a Liquid Web VPS account, I\'ve made sure that mod_deflate is installed and running/active.
I used to gzip my css and js files via PHP, as well as my PHP files th
PHP files usually serves text/html content (although you can also generate images and pretty much everything). PHP files are never sent to the client: it gets processed to generate content (text/html or images). You're looking to gzip this content.
text/html