JavaScript is a language that works with HTML to enhance web pages and make them more interactive. It allows a web designer to swap images, create windows on-the-fly, check form fields, and more.

Remember that JavaScript is not Java. Java was created by Sun Microsystems to be a robust programming language. It is a compiled language whose programs can be attached to web pages in the form of applets or used in stand-alone applications. JavaScript, on the other hand, was created by Netscape. It is a simpler language than Java. It is not compiled (like HTML code) and it is generally embedded into HTML code itself.

JavaScript in not JScript either. JScript is Microsoft's equivalent of JavaScript. Much of the code is the same and both are identified by the language="javascript". However, JavaScript and JScript are not identical. Each of these languages has the same basic qualities, but their higher end functionality differs.