As far i know until now, the min version of a .js(javascript) file is obtaining by removing the unncessary blank spaces and comments, in order to reduce the file size.
My questions are:
How can I convert a min.js file into a clear, easy readable .js file
Besides, size(&and speed) are there any other advtages of the min.js file.
the js files can be encripted?
can js be infected. I think the answer is yes, so the question is how to protect the .js files from infections?
Only the first question is most important and I'm looking for help on it.
TY
To convert a minified file into a editable source, simply open any IDE that supports auto-formatting and auto-format it. I use Netbeans to do this.
If you do client side caching for the minified file, it means to say that the client (computer) needs to process less bytes. Size and speed are the main advantages of a minified file, and they are already great advantages to prepare for a future that requires great load of data transfer. By the way, it also saves you some bandwidth on your server and therefore money.
I don't see the need of encryption. See How to disable or encrypt "View Source" for my site
Javascript files cannot be edited unless it is done so on the server. The security of your Javascript files depends on your 1) server protection 2) data protection. Data should not be able to exploit. But of course, Javascript is executed on the client side, it will be meaningless for the client user to attack him/herself. However Twitter has shown multiple Javascript exploits. You need to constantly test and check your codes against XSS, CSRF and other attacks. This means to say that if your Javascript file has a loophole, it was the developer, you, who created it.
Multiple minifiers exists, that also are able to compress JS, see http://dean.edwards.name/weblog/2007/04/packer3 for one of the most being used. Some others exists, also see the JSMin library http://www.crockford.com/javascript/jsmin.html
The main advantage is the size gain. You should also aggregate your JS files when you have multiple JS files, this also saves a lot of I/O (less HTTP requests) between the server and the client. This is probably more important than minifying.
I can't answer you about encryption. Client security will mainly depend on its browser.
EDIT: Ok my first answer is not for the first question, merged both in 2.
Related
I designed one website but I don't want to give access to end user to download my css and js files.
because If I designed one website so anybody can stolen my design by downloading my css and js files.
So is there any mechanism for secure our css and js files?
There is not really any way to secure your CSS and JS from being downloaded as the users browser needs to download these files.
One technique which is normally used to reduce CSS and JS file sizes is minification. Although it does not secure the files as such, it makes JS far harder to understand when you choose to mangle the variable names.
Online JS minifier to try out
It is not possible. Browser need to read your css file and js file. If browser can read then user can read also. You can minify your codes only e.g http://refresh-sf.com/yui/ and also you can add copyright comment blocks.
For javascript I would suggest you to use Base62 encoding.
This will also reduce the size and thus boost the performance since there will be less loading time
You can do base 62 encoding here
Other than that you cannot host your javascript file into an non downloadable form!!
Same goes with CSS too.
Once someone enters the full link the css/js files will be shown. All the files be available in the clien machine!!
To put up a plain straight answer to your question, the answer is NO
In order for visitors to see and use your site, they will have to download the necessary styles and scripts.
You can compress and obfuscate your code of course (the former actually benefits the end-user), but that's the best you can do; it won't stop someone from ripping it and using it as-is for their own nefarious purposes.
Now, your code is technically copyrighted; if you find someone who infringed on this copyright and they're using either a literal copy or a substantial part of your original work, you could theoretically sue them. Whether this is a viable approach is a tough question to answer and you will need someone with at least some kind of law degree and/or experience in this field.
Personally I would say that your chances of successful legal retribution are low, but so is the chance of someone stealing your code and profiting from it.
After searching around in Google for a while I have not had any luck or guidance in my question.
I want to be able to load up a website using javascript, ajax, in order to reduce the amount of requests needed by the server from the client. My goal is to embed/encode data within an image such that only the client needs to request this image through ajax call, and then be decoded to find the js, css, and other files needed. Then the js, css and other files will be inserted into the DOM.
If I can get the above to work then I could have a lot of flexibility on how my webapp is loaded and be able to notify the user how close the webapp is to being ready for viewing.
Currently my problem is that I cannot find how I would encode the data within an image.
Even if this is not the way to be going about serving up a webapp my curiosity is getting the best of me and I would just really like to do this.
Any guidance or pointers would be greatly appreciated!
Also: I am learning Python so if you know of a python module that I could play with that would be cool. Currently i'm playing with the pypng module to see if this could be done.
To be frank. Don't do that.
The brightest minds on earth use other methods to keep the number of requests and response time down. The most common technique for minimizing the number of requests is called Bundling. In short, you just copy'n paste all js files after each other into one big js file and all the css files into one big css file. This way you need to download two files, one js and one css. Better than that is usually not worth the trouble.
To further keep response times down you usually minify your js and css files. This is a process where all white space, comments, etc are removed and internal variable names are made as short as possible.
Finally you can serve both js and css files as gziped files to further reduce the file size to transfer.
There are many tools out there that does both bundling and minification for you. Google and pick one that suits your other tooling support.
I am trying to understand JavaScript minification and compression processes and have couple of questions on these:
Since minification makes the code difficult to debug, is it possible to do on-demand de-minification on client-side to cover-up for cases where you actually need to debug and investigate something on the website?
I remember reading somewhere that one can enable compression of all resources (like images, CSS, JavaScript etc.) by setting some options in the Apache Web Server. Is there any difference in the JavaScript compression done at Apache level and, the one done using tools like YUI Compressor?
Can someone help me know the above?
The kind-of cases where I would actually need to de-minify my JavaScript files is let's say a JavaScript error happened at line no. X. With a minified files it would be very tough to know which block of code caused that error in production as the lines are all wrapped up in a minified file. How do you guys investigate and debug in such circumstances? Another user also mentioned this debugging problem in Packed/minified javascript failing in IE6 - how to debug? questions (slightly specific to IE6 though).
You shouldn't be debugging minified code. Ideally, development process is like this:
You build and debug the site locally. You have full versions of javascripts, stylesheets and everything.
You deploy a version to production machine. You minify and gzip a copy of your assets and push that to the server. Your local development copy is left untouched.
If there's a bug in production, you modify your local version, minify, compress, upload.
Repeat until PROFIT
Chrome Dev Tools can de-obfuscate (and de-minify) javascript code if you want to debug production code (useful when trying to replicate a bug on a live environment you may not be seeing in dev)
Typically developers will develop against the uncompressed script file, compress right before deploying.
If you have to go back and debug your script files, you'd just open up the regular, uncompressed file, do your work, compress, and deploy. If you mean debug something while your website is in production, then no, you can't un-minify your script file on demand.
And yes, Apache, and even IIS, can gzip compress scripts and images automatically for you.
Since minification makes the code difficult to debug, is it possible
to do on-demand de-minification on client-side to cover-up for cases
where you actually need to debug and investigate something on the
website?
Sort of. Minified javascript has the same structure, it just does things like delete extra spaces and shorten variable names. So you can easily make the code readable again, either manually or with a script, but you can't recover variable names, so the code will still be harder to work with. So, if you have the original code, definitely don't get rid of it. Save the minified code separately.
I remember reading somewhere that one can enable compression of all
resources (like images, css, javascript etc.) by setting some options
in the Apache Web Server.
Yes, it's called gzip compression. It's not unique to apache, but you would need to configure your server to enable it.
Is there any difference in the javascript compression done at Apache
level and, the one done using tools like YUI Compressor?
Yes. YUI compressor is a minifier - the output is valid javascript. Server-side compression is more analogous to zipping a file - the browser must decode it before it can be used. Using the two together would yield the smallest filesize.
I prefer working with a local unminified copy of the JS-file, and when i deploy the site, I minify all JS-files into one. That way it is easy to debug and improve the code. However, there are tools to revert minification. Have a look at this SO post on revert minification of JavaScript.
Have a look at GZIP compression - This blog describe how to enable GZIP in Apache and how to verify that your server actually is compressing the files.
is it possible to do on-demand de-minification on client-side
Some browsers have a "pretty code" view that automatically formats source code. See Firebug's CSS tab.
Is there any difference in the javascript compression done at Apache level and, the one done using tools like YUI Compressor?
YIU Compressor is a actually a minifier. Apache compression is like ZIP-ing up the file before it is sent to the client so the actual file that is sent is smaller than the file on disk. They are two different technologies that are independent of each other.
I usually have jQuery code that is page specific along with a handful of functions that many pages share. One approach is to make seperate files for organizing, but i'm thinking that putting all the script in one file and making comments in the file for readability would also work. Then when the site goes live I can minify and obfuscate if needed.
I think the question comes down to limiting http requests or limiting file size. Is one of these a bad habit?
You can have it both ways. Develop with as many individual .js files as you need. Then use a build/deployment process that assembles the files into one larger one, then pushes them through something like Google's Closure Compiler. Compression can be handled transparently by your web server if configured properly.
Of course, this implies a structured development and deployment workflow -- e.g., with files to be assembled/compiled in a specific directory, separated from files that should be served as-is.
References:
Closure Compiler
Apache Ant
Automating the Closure Compiler with Ant
If you can put all the scripts in one file which is minified then that's what you should do first.
Also if your webserver sends out gzipped content the actual script transfer would be small, and the script will be cached on client. Since tcp transfers starts out slow and increase in speed, limiting the number of requests is the best way to speed up the overall loading of a page.
This is the same reason you see sites concatenating images into one larger image, and using CSS to display the correct part of it.
I've been using yuicompressor.jar on my test server for on-the-fly minimisation of changed JavaScript files. Now that I have deployed the website to the public server, I noticed that the server's policies forbid the use of exec() or its equivalents, so no more java execution for me.
Is there a decent on-the-fly JS compressor implemented in PHP? The only thing resembling this that I was able to find was Minify, but it's more of a full-blown compression solution with cache and everything. I want to keep the files separate and have the minimised files follow my own naming conventions, so Minify is a bit too complex for this purpose.
The tool, like yuicompressor, should be able to take either a filename or JavaScript as input and should either write to a file or output the compressed JavaScript.
EDIT: To clarify, I'm looking for something that does not have to be used as a standalone (i.e. it can be called from a function, rather than sniffing my GET variables). If I just wanted a compressor, Minify would obviously be a good choice.
EDIT2: A lot has changed in the five years since I asked this question. Today I would strongly recommend separating the front-end workflow from the server code. There are plenty of good tools for JS development around and except for the most trivial jQuery enhancements it's a better idea to have a full workflow with automated bundling, testing and linting in place and just deploy the minified bundles rather than the raw files.
Yes there is, it's called minify.
The only thing in to worry about in the way of complexity is setting up a group, and there's really nothing to it. Edit the groupsConfig.php file if you want multiple JS/CSS in one <script> or <link> statement:
return array(
'js-common' => array('//js/jquery/jquery-1.3.2.min.js', '//js/common.js', '//js/visuals.js',
'//js/jquery/facebox.js'),
'css-common' => array('//css/main.css', '//css/layout.css','//css/facebox.css')
);
To include the above 'js-common' group, do this:
<script type="text/javascript" src="/min/g=js-common"></script>
(i know i was looking for the exact same thing not knowing how to deal directly with the jar file using php - that's how i ended up here so i'm sharing what i found)
Minify is a huge library with tons of functionalities. However the minifying part is a very tiny class : http://code.google.com/p/minify/source/browse/trunk/min/lib/Minify/YUICompressor.php
& very very easy to use :
//set the path to the jar file
Minify_YUIcompressor::$jarFile=_ROOT.'libs/java/yuicompressor.jar';
//set the path to a writable temp folder
Minify_YUIcompressor::$tempDir=_ROOT.'temp/';
//minify
$yourcssminified=Minify_YUIcompressor::minifyCss($yourcssstringnotminified,$youroptions)
same process for js, if you need more functionalities just pick from the library & read the source to see how you can make direct call from your app.
I didn't read the question well, since minify is based on using the jar files, the op can't use it anyway with his server config
Minify also include other minifying methods than yui, for example:
http://code.google.com/p/minify/source/browse/trunk/min/lib/JSMinPlus.php?r=443&spec=svn468
Try Lissa:
Lissa is a generic CSS and JavaScript loading utility. Lissa is an extension of the YUI PHP Loader aimed at solving one of the current loader limitations; combo loading. YUI PHP Loader ships with a combo loader that is capable of reducing HTTP requests and increasing performance by outputting all the YUI JavaScript and/or CSS requirements as a single request per resource type. Meaning even if you needed 8 YUI components which ultimately boil down to say 13 files you would still only make 2 HTTP requests; one for the CSS and another for the JavaScript. That's great, but what about custom non-YUI resources. YUI PHP Loader will load them, but it loads them as separate includes and thus they miss out on benefits of the combo service and the number of HTTP requests for the page increases. Lissa works around this limitation by using the YUI PHP Loader to handle the loading and sort of YUI and/or custom resource dependencies and pairs that functional with Minify.