CSPP552: Web Programming, JavaScript part 14

Complicated Example

To demonstrate JavaScript in a somewhat more complex program, I wrote this program. See if you can tell what it does before clicking on the link.
If you try to look at the document source of this with Netscape, it may not be what you expect! Use wget to snarf the document.

<html>
<head><title>JavaScript Rollover Annoyance</title>
<SCRIPT LANGUAGE="JavaScript">
<!-- Mouseover stuff
 var Imageactive, Imageinactive;
 if (document.images) {
  Imageactive = new Image(100,100);    Imageactive.src = "active.gif";
  Imageinactive = new Image(100,100);  Imageinactive.src = "inactive.png";
 }

 function image_on(img) {
    if (document.images) document.images[img].src = Imageactive.src;
 }
 function image_off(img) {
    if (document.images) document.images[img].src = Imageinactive.src;
 }

 // script ends here -->
</SCRIPT>
</head>

<body bgcolor="#ffffff">
Hi there. This is annoying and useless:<p>
<SCRIPT LANGUAGE="JavaScript">
<!-- duh..

 for (i = 0; i < 6*15; i++) {
    foo = "<a href=\"javascript:;\" onMouseOver=\"image_on('Image" + i +
          "'); return true;\" onMouseOut=\"image_off('" + i +
          "'); return true;\"\><img src=\"inactive.png\" name=\"Image" + i +
          "\"  border=0 width=100 height=100\></a\>";
    document.writeln(foo); 
    if ((i+1)%6 == 0) document.writeln("<p\>"); 
 }

 // script ends here -->
</SCRIPT>
<p>
</body>
</html>