CHAPTER 1. FIRST WEBPAGE 11
a magnifying lens. Things measured in real pixels keep getting smaller.
This was a problem for webpages because images and other things got
smaller on the screen, making them harder to see.
The Non-Shrinking CSS Pixel.To solve that problem, the CSS commu-
nity came up with a revised definition of pixel. The official CSS definition
is now the width of a “standard resolution” pixel (which means 96 dots per
inch) when viewed at a distance of 28 inches (arms length). So, an item
that is 96px wide should be as wide as an inch on a ruler held at arm’s
length. Scientifically speaking, there are about 47 pixels per degree of par-
allax, looking straight on. A CSS pixel on a billboard would be a lot bigger
than a CSS pixel on an Oculus Rift virtual reality headset.
The bottom line here is that a CSS pixel could actually be many real pixels,
but it will always appear to be the same size.
Exam Question 5 (p.337): How many CSS pixels are in one degree of
direct vision?
Acceptable Answer: 47
That gets rid of the problem of shrinking pixels. The moon viewed from
earth is 24.3 pixels wide.
http://inamidst.com/stuff/notes/csspxby Sean Palmer explains more.
1.3 Seeing Your Webpage
You can probably see your webpage by simply saving it with .html at the end
of the filename, and then double-clicking it on your desktop. Your default
browser will display it.
To share your webpage it must be on a web server. Appendix 19.1.2 (page
199) explains how to put your webpage on a web server.
Your webpage must have a “name” by which people can request it. That
name is called its URL.
1.4 Version Two
We will add some very simple styling.
Insert these lines at the end of your webpage.