This property is used to set border widths around an element. More than one value may be used. The values are as follows, space delimted where more than one value is used:
One Value - With one value stated, the four border widths are the same. Two Values - With two values stated, the first will represent the top and bottom widths, the second will represent the left and right widths. Three Values - With three values stated, the first will represent the top width, the second will represent the right and left, and the third will represent the bottom width. Four Values - With four values listed, the first value will represent the top, the second will represent the right width, the third will represent the bottom, and the fourth will represent the right width.
The length measurement options for this value are:
mm millimeters. cm centimeters. in inches. pt points, which is a way of measuring the font size. One point is 1/72 (one seventy-second) of an inch. pc picas, which is yet another way of measuring font size. One pica is equal to 12 points. px pixels, which is one screen element. The display you're looking at is comprised of thousands of individual dots, each of which can change in color and luminosity to achieve the desired image. Each of these dots is referred to as a pixel. ex x-height settings, which is the height of the font's lower case letter 'x'. em em setting. One em is equivalent to the width of a capital letter in the chosen font. Millimeters, centimeters, inches, points, and picas are considered to be absolute lengths because you're specifying the exact size of the value.
Relative units such as em and ex are interpreted as references to the parent font size.
Values may also be represented as 'thin', 'medium', and 'thick'.
syntax:
document.all.elementID.style.borderWidth = "value"
This Property is used to access attributes of the following:
style