JavaScript
Who Spilled Java On My Applet?

JavaScript is a scripting language developed by Netscape. It shares many features with the programming language Java, and the two terms are therefore often erroneously used interchangeably. JavaScript is most commonly used for things like manipulating browser windows (like those pop-ups we all love so much), mouseover effects, and dropdown navigation elements. It's certainly not limited to these uses however. Check out the links here to see how it can be used for calculators, clocks, animation effects, and more.

Java Applets
This often causes confusion. Applets are not JavaScript. They're not necessarily Java, either. On the web though, they're often "java applets".

So What's An Applet?
Applet is a diminutive form of app (application), and it refers to simple, single-function programs that often ship with a larger product. Programs such as Windows' Calculator, File Manager, and Notepad are examples of applets.

DHTML
The acronym DHTML has evolved into a very loose concept that incorporates CSS, JavaScript, and HTML to create dynamic pages.

Putting JavaScript To Work
You can fairly safely implement a lot of desired common browser effects by cutting and pasting available code. Be conscious though that not all JavaScripts are functional on all platforms and browsers, and many people turn off JavaScript in their browsers to avoid pop ups.