2em is rendered as 24px??”because 20 times 1.2 is equal to 24.
Percentage measurements work exactly the same way as em measurements; 1.2% is the same as 1.2em.
The ex measurement, however, is quite different. Short for x-height, the ex measurement system is based
on the height of a lowercase x in the current font. Character heights vary quite substantially from one font
to another: At 72 pixels, an x in Times is about 32px high whereas in Arial, it??™s almost 40px. Because of the
widely varying differences, the ex measurement system is rarely used.
There are seven font-size keywords, which correspond to the HTML size attribute values 1??“7. The two
are similar in that both rely on the browser for final size interpretation, and the sizes for both are relative to
each other, as shown in Figure 8-15.
CSS specifications include two additional keywords: larger and smaller. These relative-based keywords
are obviously intended to be used in relation to the current font size. For example, in a
where the
font-size value is 10px, any text whose font-size value is larger would be rendered at about 12px,
whereas a smaller value would display text at 8px.
In Dreamweaver, the font-size property is set in the Type category of the CSS Rule Definition dialog box
or in the Relevant CSS category of the Tag inspector.
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