How to identify unused css definitions [closed]

Question

Are there any good approaches to help identify unused css definitions in a project? A bunch of css files were pulled in and now I'm trying to clean things up a bit.

Answer 1

Use Internet Explorer Developer Toolbar,s View > CSS Selector Matches: View a report of all style rules set and how many times they are used on the current page.

Answer 2

Take a look at the Firefox extension Dust-Me at https://addons.mozilla.org/en-US/firefox/addon/dust-me-selectors/.

Answer 3

I have just found this site – http://unused-css.com/

Looks good but I would need to thoroughly check its outputted 'clean' css before uploading it to any of my sites.

Also as with all these tools I would need to check it didn't strip id's and classes with no style but are used as JavaScript selectors.

The below content is taken from http://unused-css.com/ so credit to them for recommending other solutions:

Latish Sehgal has written a windows application to find and remove unused CSS classes. I haven't tested it but from the description, you have to provide the path of your html files and one CSS file. The program will then list the unused CSS selectors. From the screenshot, it looks like there is no way to export this list or download a new clean CSS file. It also looks like the service is limited to one CSS file. If you have multiple files you want to clean, you have to clean them one by one.

Dust-Me Selectors is a Firefox extension (for v1.5 or later) that finds unused CSS selectors. It extracts all the selectors from all the stylesheets on the page you're viewing, then analyzes that page to see which of those selectors are not used. The data is then stored so that when testing subsequent pages, selectors can be crossed off the list as they're encountered. This tool is supposed to be able to spider a whole website but I unfortunately could make it work. Also, I don't believe you can configure and download the CSS file with the styles removed.

Topstyle is a windows application including a bunch of tools to edit CSS. I haven't tested it much but it looks like it has the ability to removed unused CSS selectors. This software costs 80 USD.

Liquidcity CSS cleaner is a php script that uses regular expressions to check the styles of one page. It will tell you the classes that aren't available in the HTML code. I haven't tested this solution.

Deadweight is a CSS coverage tool. Given a set of stylesheets and a set of URLs, it determines which selectors are actually used and lists which can be "safely" deleted. This tool is a ruby module and will only work with rails website. The unused selectors have to be manually removed from the CSS file.

Helium CSS is a javascript tool for discovering unused CSS across many pages on a web site. You first have to install the javascript file to the page you want to test. Then, you have to call a helium function to start the cleaning.

UnusedCSS.com is web application with an easy to use interface. Type the url of a site and you will get a list of CSS selectors. For each selector, a number indicates how many times a selector is used. This service has a few limitations. The @import statement is not supported. You can't configure and download the new clean CSS file.

CSSESS is a bookmarklet that helps you find unused CSS selectors on any site. This tool is pretty easy to use but it won't let you configure and download clean CSS files. It will only list unused CSS files.

Answer 4

It looks like someone updated DustMe Selectors to work with Firefox again under a new name - 'CSS Roundup' http://blog.brothersmorrison.com/?p=198

Answer 5

Google Page Speed can do that for you (it actually does a whole lot more than just telling you which CSS is unused). On FireFox, it is available as a FireBug add-on. Then there is an online version too.

Answer 6

A Better CSS Minifier in C# dumps redundant styles;

You would also want to use Dust-Me with this.

Keep in mind, if there is any content that is not currently visible to dust-me, you might throw out styles you need.

EDIT: link was broken but archive.org has both the page and the code.