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De-obfuscating javascript code in Chrome Developer Tools

I had blogged about JavaScript debugging with Chrome Developer Tools some time back, wherein I have explained how these developer tools can help in debugging javascript code. Today Google Chrome 12 was released and my Chrome browser was updated to this version. As with every release, there have been some improvements made on performance, usability etc,. One feature that stood out for me is the ability to De-obfuscate the javascript code.

What is Minification?

Minification is the process of removing unnecessary characters such as white spaces, comments, new lines from the source code. These otherwise would be added to make the code more readable. Minifying the source code helps in reducing the file size and thereby reducing the time taken to download the file. This is the reason why most of the popular javascript libraries such as jQuery are minified. A minified jQuery file is of 31 KB in size where as an uncompressed one is about 229 KB. Unfortunately, debugging minified javascript files is an impossible task.

With the latest version of Google Chrome one can choose to de-obfuscate the javascript code right with in the developer tools. This is how the jquery.js file would look before de-obfuscation:



Now, to de-obfuscate the code one can right click on the file and select the 'De-obfuscate Source' option. This would de-obfuscate the javascript code and present the code which is readable and ready to debug:



Update:

This post was written when Chrome 12 was released. In recent versions, this option is available as a button - 'pretty print', at the bottom left corner of the screen. Look for the button with the icon '{ }'.


Comments

  1. I don't have an option for de-obfuscating the code, but I do have a new "Pretty Print" option next to the Pause Exceptions option. Seems to do the same thing.

    ReplyDelete
  2. You can right click anywhere on the javaScript and you should have 'De-obfuscate Source' option there. Are you on Chrome 12?

    ReplyDelete
  3. in chrome 13 and above it is a { } on the bottom right corner of the screen

    ReplyDelete
  4. @Adelein,

    You're right, they have now provided the option pretty print.

    ReplyDelete
  5. Oops, that's *bottom left* .. the curly brackets :)

    ReplyDelete
  6. I have update the post with the option available in recent version.

    ReplyDelete
  7. Thelle Hedegaard KristensenJune 7, 2013 at 9:12 PM

    Thanks for sharing! Is there something similar for minified CSS?

    ReplyDelete
  8. We've launched a new Javascript Obfuscator called http:///www.javascript2img.com.

    It embeds the JS code into a image.

    It's free and hope to he helpful ...

    ReplyDelete

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