Using Minify is a simple method to reduce the size of Javascript files.

Another helpful technique is enabling compression (zip) at the web server level.

Instead of making direct modifications to your files, my suggestion would be to opt for compression. Many clients are compatible with this method.

You may discover that this approach is not only simpler but also equally efficient.

Check out more insights from Jeff's experiences.

Reducing file sizes through compression and removal of whitespace is a good starting point.

In addition:

1. Consolidate all JavaScript and CSS files into one single file for faster downloading by the browser. This consolidation should be part of your build process.

2. Enable caching at the web-server level using the cache-control HTTP header. Set the expiration time to a longer period (such as a year) so that the browser only needs to download the content once. To account for future updates, include a version number in the query string like this:

<script src="my_js_file.js?1.2.0.1" type="text/javascript"></script>

<link rel="stylesheet" type="text/css" href="my_css_file.css?3.1.0.926" />

I find it interesting that there hasn't been any mention of compressing your code using gzip. This could potentially result in a significant reduction of around 50%!

Discover these handy online resources for simplifying your coding tasks:

• To compress JavaScript code, check out JavaScript Code Compressor. It's currently known as the top tool for minifying or un-minifying JS.

• If you need to minify CSS code, try using CSS Minifier Tool. This tool is highly recommended for simplifying CSS.

The tools mentioned above could be very helpful for improving your coding efficiency.

Take a look at this question: Optimal javascript compression tool

Your selection of a compressor might be influenced by whether or not you plan to gzip your JavaScript files. (At present, Packer may not be the most suitable option if you intend to gzip as well, but refer to the linked question for the latest recommendations)

Dojo Shrinksafe is an effective Javascript compressor that utilizes a genuine JS interpreter, ensuring that your code remains intact. While other compressors may perform decently, Shrinksafe stands out as an ideal choice for inclusion in a build script, saving you the hassle of re-testing the compressed script.

If you're looking to optimize your code, consider using Shrinksafe: . Our team has found it to be quite effective and we integrate it into our web app packaging process using an ant build.

Tips for Optimizing Your JavaScript Code offers valuable insights on maximizing savings through script tweaks.

Google offers a selection of pre-compressed JavaScript library files that can be easily integrated into your website. By utilizing Google's bandwidth and taking advantage of most browsers' file caching systems, users may already have certain files downloaded from Google for other websites, saving time and resources when accessing your site. This is a convenient feature for the vast array of JS libraries available on the web.

When it comes to optimizing JavaScript, I rely on Dean Edwards's Javascript Packer. This tool has been adapted for multiple languages, making it a versatile choice for developers.

JavaScript compression can take different forms - from simply removing comments and whitespace to altering variable names for efficiency. Some methods use advanced techniques like eval() function, which may impact client performance. It's important to choose the right compression level based on your project requirements.

For CSS optimization, eliminating whitespace and comments is key. You can achieve this with a compact function:

function compressCSS($css) {
    return
        preg_replace(
            array('@\s\s+@','@(\w+:)\s*([\w\s,#]+;?)@'),
            array(' ','$1$2'),
            str_replace(
                array("\r","\n","\t",' {','} ',';}'),
                array('','','','{','}','}'),
                preg_replace('@/\*[^*]*\*+([^/][^*]*\*+)*/@', '', $css)
            )
        )
    ;
}

In addition to optimizing individual files, consider reducing HTTP requests by combining JavaScript and CSS files. I've developed a tool discussed on my blog () that streamlines this process, offering customizable options for file aggregation and compression.

The build script allows you to merge and minimize multiple files into one, enhancing site performance. The program source code is available for further customization.

The YUI Compressor excels in efficiently compressing both Javascript and CSS files.

My choice goes to YUI Compressor because it does more than just using regular expressions to compress code. It creates a parse tree of the code, similar to how a Javascript interpreter works, and then compresses it intelligently. This approach allows for careful compression of identifiers.

Furthermore, YUI Compressor also offers a CSS compression feature that I have yet to explore extensively.

CssTidy stands out as a top-notch CSS optimizer in my opinion. It has the capability to remove comments, get rid of unnecessary white spaces, and utilize shorthand rules as nickf suggested. Additionally, compressing the final output is beneficial, as pointed out by others.

The results can show a significant compression ratio, giving you the freedom to heavily comment your CSS without concerns about file size.

However, this level of preprocessing may interact with common "css hacks" in unforeseeable ways. Some hacks may work, some may not, and adjustments might be needed which could impact compression levels on other elements (especially comments).

One helpful tool I came across is JSCompress. It not only minifies JavaScript but also allows you to merge multiple scripts together, which can be beneficial if you only need to use them once. I was able to save 70% of space before compression and a similar amount after compressing as well.

Don't forget to re-add any copyright notices that may have been removed during the compression process.