Protecting JavaScript Code with Jasob JavaScript Obfuscator

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  • June 25, 2009

JavaScript is a de-facto standard scripting language for Web automation. Used on billions of Web pages and recognized by all modern Web browsers, the language earned popularity among Web developers worldwide.

JavaScript applets used in Web pages cannot be compiled to produce an executable file. Due to the interpreting nature of scripting languages, JavaScript applications are embedded into Web pages in the form of source code, which means that the full script is available for anyone to view and to borrow. Up until now, little could be done to prevent copyright infringements occurring from such ‘borrowing’ of JavaScript code. All it takes for someone to gain access to the full source code of a script is viewing the source code of the page opened in a Web browser. Needless to say, this can be done by pretty much everyone.

Web developers concerned with protecting their hard-written code are seeking ways to encrypt the source code of JavaScript applications to at least make it more difficult to understand, modify and re-use. Up until now, they had to manually process each and every JavaScript they create in order to obfuscate the code.

Today, there is a solution helping Web developers to automate JavaScript protection. Jasob JavaScript Obfuscator ( makes it easy for anyone to protect JavaScript applications by obfuscating and compressing the source code. Obfuscated JavaScript applets look illegible to a human being, yet they are essentially exactly the same thing from the point of view of a Web browser.

Jasob JavaScript Obfuscator encrypts JavaScript code by performing a number of changes to the source code. The obfuscator replaces variables and function names with random, meaningless values, making it extremely hard for the human developer to understand what the entire thing is supposed to do. By replacing descriptive names with shorter strings without a meaning, Jasob JavaScript Obfuscator not only protects JavaScript files, but makes them smaller, too. To achieve additional JavaScript compression, Jasob JavaScript Obfuscator removes extra whitespaces and tabbing and deletes all comments. Effective compression rate for an average JavaScript application can reach as much as 70%!

Jasob JavaScript Obfuscator can process JavaScript applets and CSS code in similar ways. CSS files will become smaller and cryptic for casual viewers, allowing Web developers to better defend their intellectual property. In addition, Jasob JavaScript Obfuscator can compress other types of files such as HTML by removing whitespaces and comments to make the files smaller.

Jasob JavaScript Obfuscator is highly customizable and easy to learn and to use. The available GUI and command-line interfaces allow point-and-click operation as well as comprehensive automation of routine JavaScript protection tasks. The ability to configure Jasob JavaScript Obfuscator in a point-and-click fashion and to use a command-line tool with saved project settings makes command-line automation an easy thing.

Jasob JavaScript Obfuscator is available to Web developers as a free evaluation version. Download your free trial copy at:

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