The VBScript portion returns a random number between 1 and 12 as so:
rn=Int(12 * rnd())
The output is produced through document.write but placed inside a hidden SPAN tag. We don't need to see the number, but we need to have it.
qts = "Styrofoam is not made from kittens";
Then there's qts before it, so on, and it ends at 11.
The main action of the fact generator is this statement:
document.all["display"].innerHTML="Random Fact: <font color=\"#666666\">"+qts[number]+"</font> ";
document.all["display"].innerHTML means that the fact will be inserted into the span with the id of display. Finally qts[number] says that the fact will come from the array named qts and the number will be the vbscript random number (imported via the innerHTML of the hidden SPAN).
Example: if number=5;
qts[number] would return "The other UFO was an upside down salad spinner"