https://github.com/ndreckshage/CSSVacuum

optimize your critical rendering path
https://github.com/ndreckshage/CSSVacuum

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optimize your critical rendering path

• Host: GitHub
• URL: https://github.com/ndreckshage/CSSVacuum
• Owner: ndreckshage
• License: mit
• Created: 2013-09-08T20:35:04.000Z (over 11 years ago)
• Default Branch: master
• Last Pushed: 2013-09-11T22:18:33.000Z (over 11 years ago)
• Last Synced: 2024-08-03T05:22:31.585Z (9 months ago)
• Size: 344 KB
• Stars: 45
• Watchers: 4
• Forks: 4
• Open Issues: 2
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
CSSVacuum

======

_optimize your critical rendering path_

__created at tech crunch disrupt sf 2013__

![CSSVacuum](https://raw.github.com/ndreckshage/CSSVacuum/master/images/cssvacuum.jpg)

Critical Rendering Path

=======================

Ilya Grigorik gave a great talk at Velocity on the [Critical Rendering Path](http://bit.ly/mobilecrp). Please check out his full presentation, but essentially, above the fold CSS should be inlined, and external CSS should by loaded asynchronously.

Eventually, this could work with the [mod_pagespeed filter](https://developers.google.com/speed/pagespeed/module/filter-prioritize-critical-css), so you don't have to determine the relevant styles manually.

CSSVacuum is...

===============

a tool to help determine what css if 'critical'. It is a Chrome content script (extension) that will

+ determine all styles that are called **above the fold**

+ provide css to copy and paste into the new inlined header

+ provide a nice animation while it works

CSSVacuum isnt...

=================

+ an out of the box solution to automatically inline css

+ ready for production

Example use in production...

============================

+ setup a PhantomJS script, that utilizes portions of Chrome extension.

+ job that triggers Phantom to hit all relative pages on deploy (and clear existing cache keys)

+ cache the resulting CSS

+ if cache key exists, serve critical CSS inline, and full CSS async in footer

Install (official)

==================

+ https://chrome.google.com/webstore/detail/cssvacuum/maellbbeahlpainnadomcgbcgmhjkbac

Install (source)

================

+ clone the repo

+ open Chrome and go to [extensions](chrome://extensions)

+ click developer mode, load unpacked extensions, and select repo

+ enable CSSVacuum

Use

===

+ with CSSVacuum installed, go to any url with ?CSSVacuum in query string. "http://amazon.com?CSSVacuum", for example.

+ click the CSSVacuum button

+ copy and paste the resulting css

Todo

====

+ Lots of room for improvement

+ Eliminate unecessary selectors (right now any selector, regardless of specificity, is included if it matches a class name)

+ Do guess work to limit resulting CSS filesize down to 14k.

+ PhantomJS script for production use.