The following is a table of numbers and their factorials. The JavaScript factorial
function is defined in the <head> of this document, and called
by JavaScript within this <table> element.
It would be better style to define the <table> completely
within the JavaScript, rather than doing part of it in HTML and part in JavaScript.
I did it this way to emphasize that JavaScript and HTML can be arbitrarily
mixed together.
The following example is more complex. It uses an HTML <form> to
input and output data, does some validity checking, and displays an alert box
for invalid entries.