Even if your site is great, the best in the world, if your audience can't see it, then what good is it? One important factor for good design is compatability.
      Using too many types of new technology can create beautiful, intereactive, stupendous webpages. But if the reader can't use those technologies, then what good is using it? Your reader won't be able to see those wonderful elements you put in.
      Even if you put a hyperlink to a website where they can download the browser/plugin that they need, the reader will be so annoyed from installing the thing that they won't even remember your lame old site. Or even worse, they won't even take the time to get the plugin.
      If you do include many plugins, such as Macromedia Flash elements, VRML, RealPlayer, ActiveX objects, excessive JavaScript, and a dozen others, be kind enough to provide a link to the website where the reader may obtain the necessary plugin for their browser.
      But you can save your reader's sanity by sticking with HTML, some JavaScript, a bit of CSS, and a tad of Java. Most newer browsers can support all those technologies, and the older ones just won't use the newer ones; they will display the straight-out HTML, at least giving the reader a preview of your page. If most of your content is in plugins, then your reader won't be able to see anything if they don't have the plugin.
      By "straight-out" HTML, I mean HTML that has been approved in the W3C standard. Don't include any browser specific tag, such as <blink> or <marquee>. Two reasons: first, both of those tags are just plain ugly (as are many browser specific tags), and secondly, they won't work with any other browser besides the proprietary one; the <blink> tag is only supported by Netscape Navigator, while the <marquee> tag is only supported by Microsoft Internet Explorer.
      You really don't need to use advanced plugins for a small webpage; HTML and a bit of dynamic effects will do very nicely. But should you decide to add some extra programming, each type has their own functions.

• HTML - HTML is the basis of any webpage. Although many functions can be replaced by JavaScript and CSS, you still need some of this.
• JavaScript - This versatile scripting language (a type of language intermediate between markup languages, i.e., HTML, and full blown languages, i.e., Java) is best suited for dynamic effects. Dynamic effects are the pinnacle of interactivity today. JavaScript gives life to forms, can introduce animations that are not images, and can used to create other effects, such as the hovering underline of the links here.
• Java - Java, because of it's robustness (see Inroduction to Java in Java by Justin Seyster) is better suited for independent, self contained applets. These applets can be anything; there's a great listing of applets at Gamelan. Java is not quite suited for dynamic effects that have to deal with HTML. JavaScript is much better. However, within the Java applet, nothing can beat it for interactivity.
• CSS - Cascading Stylesheets. This really isn't a programming language, since all it can do is define the visual characteristics for HTML elements. CSS can make the job of creating consistent webpage considerably easier; using CSS, you can create a single document that describes the font for the page, the color of a table, and the text-decoration for links, and every webpage will display those changes. When used in conjunction with JavaScript, dynamic effects in HTML are unsurpassed. And it's an easy language, to boot!

With a knowledge of compatability issues, you can save your readers a headache. So how can you do things with just plain ol' HTML. Take a look at a few tips and tricks.