In this article, we will consider approaches to detect obfuscated JavaScript code snippets using machine learning. Most websites use JavaScript (JS) code to make dynamic content; thus, JS code becomes a valuable attack vector against browsers, browser plug-ins, email clients, and other JS applications. Among common JS-based attacks are drive-by-download, cross-site scripting (XSS), cross-site request forgery (XSRF), malvertising/malicious advertising, and others. Most of the malicious JS codes are obfuscated in order to hide what they are doing and to avoid being detected by signature-based security systems. In other words, the obfuscation technique is a sequence of confusing code transformations to compromise its understandability, but at the same time to save its functionality.