Editing X-height (section)

==Use in web design==
In [[computing]] one use of x-height is as a unit of measurement in [[web page]]s.  In [[Cascading Style Sheets|CSS]] and [[LaTeX]] the x-height is called an ''ex''.  The use of ex in dimensioning objects, however, is less stable than use of the [[em (typography)|em]] across [[web browser|browser]]s.  [[Internet Explorer]], for example, dimensions ex at exactly one half of em, whereas [[Mozilla Firefox]] dimensions ex closer to the actual x-height of the [[font]], rounded relative to the font's current [[pixel]] height.  Thus, the exact ratio of ex to em can vary by font size within a browser if the determined values are rounded to the nearest whole unit.  For example, a browser calculating an x-height of 45% on a font 10 pixels tall may round ex to either 4 pixels or 5 pixels or leave it at 4.5 pixels.