Appendix G

 

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G. JavaScript and HTML Color Names and Values

HTML and JavaScript allow colors to be specified for such things as text color, link color, document background, and even the background of table cells. Colors can be specified in a fully general #RRGGBB format, in which RR, GG, and BB are each two hexadecimal digits which represent the intensity of red, green, and blue primaries in the color. Two hexadecimal digits provide 8 color values, or 256 possible levels for each of the red, green, and blue primaries. Using the color specification scheme, you would use "#000000" for black and "#FFFFFF" for white. "#00FF00" would produce a very intense green, and "#A0A0A0" would produce a gray color.

Because it can be difficult to determine the hexadecimal values for the colors you desire, HTML and JavaScript also allow certain colors to be specified by name. The HTML 3.2 standard defines sixteen standard color names that should be supported by all conforming browsers. These colors are listed in Table G.1. This list of sixteen colors was chosen to match the 16 colors supported on old VGA display hardware. Note that the HTML 3.2 standard does not specify the actual color values for each of these named colors, so they may be displayed somewhat differently by different browsers.

Navigator 2.0 and 3.0 and Internet Explorer 3.0 each support all of the standard colors listed in Table G.1. In addition to these standard colors, Navigator also recognizes quite a few other color names, which are listed in Table G.2. Because these color names are not standardized in any way,[1] it is not really a good idea to rely on them in production web pages that may be viewed on web browsers that do not support these color names. For that reason, Table G.2 also lists the hexadecimal color string equivalents for each of these colors. If you use the color name while developing a JavaScript program, you can replace it with the corresponding color value for the release version of that program.

[1] Programmers familiar with the X Window System may recognize the color names in this table, at least the bizarre ones such as "papayawhip"; the color names and values are derived from the "color database" shipped with the X11 distribution.

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Examples		LiveConnected Navigator Plug-Ins

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