mod_pagespeed Filter Examples

Here are some of the most useful filters provided by mod_pagespeed. Each one has a simple HTML example attached; click "before" to see the original file, and "after" to see what mod_pagespeed produces with that filter (and only that filter) enabled. The two versions should look exactly the same, but the "after" one will be (slightly) speedier. Use "view source" to see the mod_pagespeed difference!

add_instrumentation Adds client-side latency instrumentation. before after
extend_cache Improves cacheability. before after
collapse_whitespace Removes unnecessary whitespace in HTML. before after
combine_css Combines multiple CSS files into one. before after
combine_heads Combines multiple <head> elements into one. before after
move_css_to_head Moves CSS into the <head> element. before after
elide_attributes Removes unnecessary attributes in HTML tags. before after
inline_css Inlines small external CSS files. before after
inline_javascript Inlines small external Javascript files. before after
outline_css Moves large inline <style> tags into external files for cacheability. before after
outline_javascript Moves large inline <script> tags into external files for cacheability. before after
remove_quotes Removes unnecessary quotes in HTML tags. before after
remove_comments Removes HTML comments. before after
rewrite_css Minifies CSS. before after
rewrite_images Rescales, and compresses images; inlines small ones. before after
rewrite_javascript Minifies Javascript. before after