It is known that minifying the JavaScript and CSS files can really reduce the files size and improve the general site performance. Lot of sites (BlogEngine.NET among them)  do it on run-time and not it the build time. At this point, I want to recommend the JavaScript minifier JSMIN by Douglas Crockford. It does the job very good, and by far, much faster than all the RegularExpression \ Replace minifiers. Because in my Compression project MbCompression I do the minifying on run-time, I decided to use jsmin minifier.

The Css minifier

All the Css minifiers I found are using Regular Expression\ Replace to remove the unneeded characters. This is working fine, but have a realy bad performance, special on run-time. The speed is slow (special using the Regular Expression), and another important thing is, every Replace creates a very big string in the memory! (Strings are immutable, remember?), so if you have several Replaces, it creates several big strings in the server memory!

To improve performance, I took  JSMIN idea, that are not using any strings in the memory, and perform the minifying much faster, and created a CSS minifier that produce a small CSS file, much faster, and with much less memory overhead.

This minifier was tested on several CSS files. Feel free to download it and use it. If there is any file that not been minify correctly, send it to me, and I will try to improve the minifier.

CssMinifier.cs (9.59 kb)

My last version of the compression module was working great and able to compress and cache pages, WebResources, CSS and JavaScripts files. It have one problem (that similiar to most of the compression modules you can find). To compress the javascripts files, you have to modify the way you register them and change their links to something like that: 

needs to became 

It is not so hard work to do, but it became useless when you use third party controls as 'Telerik' (RadControls)  and force it to doesn't use it's scripts as WebResources. In such case, the controls 'Injects' their scripts links into the HTML code and you can't modify them as needed to let the compression handler to compress it.  In the new version of my compression component, I added a ResponseFilter that parse the Scripts links in the HTML and convert them into 'compressable' links. By default, this option is disabled in the compression module. To enable it (if you use such third party controls), just add the attribute compressThirdParityScripts="true" to the compression configuration.

Full implementation instructions can be found here: Compression module implementation 

Latest code can be downloaded from: http://www.codeplex.com/MbCompression