attributes: size, width, noshade, and align, as well as the color attribute which is not

supported in all browsers.

The standard rule is drawn across the full width of the page. To adjust the length we

can use the width attribute, specified in pixels or a percentage.

Normally, browsers render the rule two pixels thick. This can be changed with the size attribute

to any number of pixels.

Also, the rule has two gray shades with the same fill color as the background. If we add

the noshade attribute it will instead be displayed in one solid color. This attribute does not

require a value, however we can use the attribute's own name as its value.

If we want another color then gray we can use the color attribute.

We can also align the rule to either the left or right, or center it which is the default.