google有对apache优化的mod_pagespeed，nginx的优化工具ngx_pagespeed
ngx_pagespeed speeds up your site and reduces page load time by automatically applying web performance best practices to pages, and associated assets (CSS, JavaScript, images) without requiring that you modify your existing content or workflow. Features (will) include:
- Image optimization: stripping meta-data, dynamic resizing, recompression
- CSS & JavaScript minification, concatenation, inlining, and outlining
- Small resource inlining
- Deferring image and JavaScript loading
- HTML rewriting
- Cache lifetime extension
- and more
来源：oschina
链接：https://my.oschina.net/u/105637/blog/98939