A set of program instructions, vaguely similar to- Java- but not actually related, written straight into the HTML of a webpage instead of as an applet.
— Computer ScienceA scripting language targeted specifically to the Internet. It is the first scripting language to fully conform to ECMAScript, the Web’s only standard scripting language. Despite its name, JavaScript is not a derivative of Java; its origin is Netscape’s Livescript language.
— Computer Science