The System.Web.UI.WebControls.FontSize enumeration represents the font sizes defined by HTML 4.0. The font size can be an absolute or relative size.
An absolute font size represents a predefined font size determined by the browser. The possible values for an absolute font size are FontSize.XXSmall, FontSize.XSmall, FontSize.Small, FontSize.Medium, FontSize.Large, FontSize.XLarge, and FontSize.XXLarge.
A relative font size represents a font size one size larger or smaller than a parent element's font size. The possible values for a relative font size are FontSize.Smaller and FontSize.Larger.
Some browers do not recognize FontSize.Smaller and FontSize.Larger font sizes. Check with your browser for compatibility.