HTML Lessons (HTML සිංහලෙන් ) for A/L Student Part 2 Comment and Color

    

                                                HTML (COMMENT AND COLOR) 

          HTML COMMENT

       

This template produces a rendering of an HTML comment..

{{Example HTML comment|Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.}}

will produce:

<!-- Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. -->

    

                                       WEB COLOR

Web colors are colors used in displaying web pages on the World Wide Web, and the methods for describing and specifying those colors. Colors may be specified as an RGB triplet or in hexadecimal format (a hex triplet) or according to their common English names in some cases. A color tool or other graphics software is often used to generate color values. In some uses, hexadecimal color codes are specified with notation using a leading number sign (#).[1][2] A color is specified according to the intensity of its red, green and blue components, each represented by eight bits. Thus, there are 24 bits used to specify a web color within the sRGB gamut, and 16,777,216 colors that may be so specified.

Colors outside the sRGB gamut can be specified in Cascading Style Sheets by making one or more of the red, green and blue components negative or greater than 100%, so the color space is theoretically an unbounded extrapolation of sRGB similar to scRGB.[3] Specifying a non-sRGB color this way requires the RGB() function call; it is impossible with the hexadecimal syntax (and thus impossible in legacy HTML documents that do not use CSS).

The first versions of Mosaic and Netscape Navigator used the X11 color names as the basis for their color lists, as both started as X Window System applications. Web colors have an unambiguous colorimetric definition, sRGB, which relates the chromaticities of a particular phosphor set, a given transfer curve, adaptive whitepoint, and viewing conditions.[4] These have been chosen to be similar to many real-world monitors and viewing conditions, in order to allow rendering to be fairly close to the specified values even without color management. User agents vary in the fidelity with which they represent the specified colors. More advanced user agents use color management to provide better color fidelity; this is particularly important for Web-to-print applications.

Hex triplet

Shorthand hexadecimal form[edit]

An abbreviated, three (hexadecimal)-digit form is used.^[5] Expanding this form to the six-digit form is as simple as doubling each digit: 09C becomes 0099CC as presented on the following CSS example:

.threedigit { color: #09C;    }
.sixdigit   { color: #0099CC; } /* same color as above */

This shorthand form reduces the palette to 4,096 colors, equivalent of 12-bit color as opposed to 24-bit color using the whole six-digit form (16,777,216 colors), this limitation is sufficient for many text based documents.

HTML color names[edit]

The HTML 4.01 specification, ratified in 1999, defines 16 named colors,^[6] as follows (names are defined in this context to be case-insensitive):

CSS 1–2.0, HTML 3.2–4, and VGA color names

Name	Hex (RGB)	Red (RGB)	Green (RGB)	Blue (RGB)	Hue (HSL/HSV)	Satur. (HSL)	Light (HSL)	Satur. (HSV)	Value (HSV)	CGA number (name); alias
White	#FFFFFF	100%	100%	100%	0°	0%	100%	0%	100%	15 (white)
Silver	#C0C0C0	75%	75%	75%	0°	0%	75%	0%	75%	07 (light gray)
Gray	#808080	50%	50%	50%	0°	0%	50%	0%	50%	08 (dark gray)
Black	#000000	0%	0%	0%	0°	0%	0%	0%	0%	00 (black)
Red	#FF0000	100%	0%	0%	0°	100%	50%	100%	100%	12 (high red)
Maroon	#800000	50%	0%	0%	0°	100%	25%	100%	50%	04 (low red)
Yellow	#FFFF00	100%	100%	0%	60°	100%	50%	100%	100%	14 (yellow)
Olive	#808000	50%	50%	0%	60°	100%	25%	100%	50%	06 (brown)
Lime	#00FF00	0%	100%	0%	120°	100%	50%	100%	100%	10 (high green); green
Green	#008000	0%	50%	0%	120°	100%	25%	100%	50%	02 (low green)
Aqua	#00FFFF	0%	100%	100%	180°	100%	50%	100%	100%	11 (high cyan); cyan
Teal	#008080	0%	50%	50%	180°	100%	25%	100%	50%	03 (low cyan)
Blue	#0000FF	0%	0%	100%	240°	100%	50%	100%	100%	09 (high blue)
Navy	#000080	0%	0%	50%	240°	100%	25%	100%	50%	01 (low blue)
Fuchsia	#FF00FF	100%	0%	100%	300°	100%	50%	100%	100%	13 (high magenta); magenta
Purple	#800080	50%	0%	50%	300°	100%	25%	100%	50%	05 (low magenta)

These 16 were labelled as sRGB and included in the HTML 3.0 specification, which noted they were "the standard 16 colors supported with the Windows VGA palette."^[7]

X11 color names[edit]

SVG Version of X11 color names

Main article: X11 color names

A number of colors are defined by web browsers. A particular browser may not recognize all of these colors, but as of 2005, all modern, general-use, graphical browsers support the full list of colors. Many of these colors are from the list of X11 color names distributed with the X Window System. These colors were standardized by SVG 1.0, and are accepted by SVG Full user agents. They are not part of SVG Tiny.

The list of colors shipped with the X11 product varies between implementations and clashes with certain of the HTML names such as green. X11 colors are defined as simple RGB (hence, no particular color space), rather than sRGB. This means that the list of colors found in X11 (e.g., in /usr/lib/X11/rgb.txt) should not directly be used to choose colors for the web.^[8]

The list of web "X11 colors" from the CSS3 specification, along with their hexadecimal and decimal equivalents, is shown below. Compare the alphabetical lists in the W3C standards. This includes the common synonyms: aqua (HTML4/CSS 1.0 standard name) and cyan (common sRGB name), magenta (common sRGB name) and fuchsia (HTML4/CSS 1.0 standard name), gray (HTML4/CSS 1.0 standard name) and grey.^[9][10]

HTML name	R   G   B
	Hex	Decimal
Pink colors
Pink	FF C0 CB	255 192 203
LightPink	FF B6 C1	255 182 193
HotPink	FF 69 B4	255 105 180
DeepPink	FF 14 93	255  20 147
PaleVioletRed	DB 70 93	219 112 147
MediumVioletRed	C7 15 85	199  21 133
Red colors
LightSalmon	FF A0 7A	255 160 122
Salmon	FA 80 72	250 128 114
DarkSalmon	E9 96 7A	233 150 122
LightCoral	F0 80 80	240 128 128
IndianRed	CD 5C 5C	205  92  92
Crimson	DC 14 3C	220  20  60
Firebrick	B2 22 22	178  34  34
DarkRed	8B 00 00	139   0   0
Red	FF 00 00	255   0   0
Orange colors
OrangeRed	FF 45 00	255  69   0
Tomato	FF 63 47	255  99  71
Coral	FF 7F 50	255 127  80
DarkOrange	FF 8C 00	255 140   0
Orange	FF A5 00	255 165   0
Yellow colors
Yellow	FF FF 00	255 255   0
LightYellow	FF FF E0	255 255 224
LemonChiffon	FF FA CD	255 250 205
LightGoldenrodYellow	FA FA D2	250 250 210
PapayaWhip	FF EF D5	255 239 213
Moccasin	FF E4 B5	255 228 181
PeachPuff	FF DA B9	255 218 185
PaleGoldenrod	EE E8 AA	238 232 170
Khaki	F0 E6 8C	240 230 140
DarkKhaki	BD B7 6B	189 183 107
Gold	FF D7 00	255 215   0
Brown colors
Cornsilk	FF F8 DC	255 248 220
BlanchedAlmond	FF EB CD	255 235 205
Bisque	FF E4 C4	255 228 196
NavajoWhite	FF DE AD	255 222 173
Wheat	F5 DE B3	245 222 179
Burlywood	DE B8 87	222 184 135
Tan	D2 B4 8C	210 180 140
RosyBrown	BC 8F 8F	188 143 143
SandyBrown	F4 A4 60	244 164  96
Goldenrod	DA A5 20	218 165  32
DarkGoldenrod	B8 86 0B	184 134  11
Peru	CD 85 3F	205 133  63
Chocolate	D2 69 1E	210 105  30
SaddleBrown	8B 45 13	139  69  19
Sienna	A0 52 2D	160  82  45
Brown	A5 2A 2A	165  42  42
Maroon	80 00 00	128   0   0

 

HTML name	R   G   B
	Hex	Decimal
Green colors
DarkOliveGreen	55 6B 2F	85 107  47
Olive	80 80 00	128 128   0
OliveDrab	6B 8E 23	107 142  35
YellowGreen	9A CD 32	154 205  50
LimeGreen	32 CD 32	50 205  50
Lime	00 FF 00	0 255   0
LawnGreen	7C FC 00	124 252   0
Chartreuse	7F FF 00	127 255   0
GreenYellow	AD FF 2F	173 255  47
SpringGreen	00 FF 7F	0 255 127
MediumSpringGreen	00 FA 9A	0 250 154
LightGreen	90 EE 90	144 238 144
PaleGreen	98 FB 98	152 251 152
DarkSeaGreen	8F BC 8F	143 188 143
MediumAquamarine	66 CD AA	102 205 170
MediumSeaGreen	3C B3 71	60 179 113
SeaGreen	2E 8B 57	46 139  87
ForestGreen	22 8B 22	34 139  34
Green	00 80 00	0 128   0
DarkGreen	00 64 00	0 100   0
Cyan colors
Aqua	00 FF FF	0 255 255
Cyan	00 FF FF	0 255 255
LightCyan	E0 FF FF	224 255 255
PaleTurquoise	AF EE EE	175 238 238
Aquamarine	7F FF D4	127 255 212
Turquoise	40 E0 D0	64 224 208
MediumTurquoise	48 D1 CC	72 209 204
DarkTurquoise	00 CE D1	0 206 209
LightSeaGreen	20 B2 AA	32 178 170
CadetBlue	5F 9E A0	95 158 160
DarkCyan	00 8B 8B	0 139 139
Teal	00 80 80	0 128 128
Blue colors
LightSteelBlue	B0 C4 DE	176 196 222
PowderBlue	B0 E0 E6	176 224 230
LightBlue	AD D8 E6	173 216 230
SkyBlue	87 CE EB	135 206 235
LightSkyBlue	87 CE FA	135 206 250
DeepSkyBlue	00 BF FF	0 191 255
DodgerBlue	1E 90 FF	30 144 255
CornflowerBlue	64 95 ED	100 149 237
SteelBlue	46 82 B4	70 130 180
RoyalBlue	41 69 E1	65 105 225
Blue	00 00 FF	0   0 255
MediumBlue	00 00 CD	0   0 205
DarkBlue	00 00 8B	0   0 139
Navy	00 00 80	0   0 128
MidnightBlue	19 19 70	25  25 112

 

HTML name	R   G   B
	Hex	Decimal
Purple, violet, and magenta colors
Lavender	E6 E6 FA	230 230 250
Thistle	D8 BF D8	216 191 216
Plum	DD A0 DD	221 160 221
Violet	EE 82 EE	238 130 238
Orchid	DA 70 D6	218 112 214
Fuchsia	FF 00 FF	255   0 255
Magenta	FF 00 FF	255   0 255
MediumOrchid	BA 55 D3	186  85 211
MediumPurple	93 70 DB	147 112 219
BlueViolet	8A 2B E2	138  43 226
DarkViolet	94 00 D3	148   0 211
DarkOrchid	99 32 CC	153  50 204
DarkMagenta	8B 00 8B	139   0 139
Purple	80 00 80	128   0 128
Indigo	4B 00 82	75   0 130
DarkSlateBlue	48 3D 8B	72  61 139
SlateBlue	6A 5A CD	106  90 205
MediumSlateBlue	7B 68 EE	123 104 238
White colors
White	FF FF FF	255 255 255
Snow	FF FA FA	255 250 250
Honeydew	F0 FF F0	240 255 240
MintCream	F5 FF FA	245 255 250
Azure	F0 FF FF	240 255 255
AliceBlue	F0 F8 FF	240 248 255
GhostWhite	F8 F8 FF	248 248 255
WhiteSmoke	F5 F5 F5	245 245 245
Seashell	FF F5 EE	255 245 238
Beige	F5 F5 DC	245 245 220
OldLace	FD F5 E6	253 245 230
FloralWhite	FF FA F0	255 250 240
Ivory	FF FF F0	255 255 240
AntiqueWhite	FA EB D7	250 235 215
Linen	FA F0 E6	250 240 230
LavenderBlush	FF F0 F5	255 240 245
MistyRose	FF E4 E1	255 228 225
Gray and black colors
Gainsboro	DC DC DC	220 220 220
LightGray	D3 D3 D3	211 211 211
Silver	C0 C0 C0	192 192 192
DarkGray	A9 A9 A9	169 169 169
Gray	80 80 80	128 128 128
DimGray	69 69 69	105 105 105
LightSlateGray	77 88 99	119 136 153
SlateGray	70 80 90	112 128 144
DarkSlateGray	2F 4F 4F	47  79  79
Black	00 00 00	0   0   0

Web-safe colors[edit]

Color depth
1-bit monochrome 8-bit grayscale 8-bit color 15- or 16-bit color (high color) 24-bit color (true color) 30-, 36-, or 48-bit color (deep color)
Related
Indexed color Palette RGB color model Web-safe color
v t e

In the mid-90s, many displays were only capable of displaying 256 colors.^[11] These may be dictated by the hardware or changeable by a "color table". When a color is found (e.g., in an image) that is not one available, a different one had to be used. This can be done by either using the closest color, or by using dithering.

There were various attempts to make a "standard" color palette. A set of colors was needed that could be shown without dithering on 256-color displays; the number 216 was chosen partly because computer operating systems customarily reserved sixteen to twenty colors for their own use; it was also selected because it allows exactly six equally spaced shades of red, green, and blue (6 × 6 × 6 = 216), each from 00 to FF (including both limits).

The list of colors is presented as if it had special properties that render them immune to dithering, but on 256-color displays applications can actually set a palette of any selection of colors that they choose, dithering the rest. These colors were chosen specifically because they matched the palettes selected by various browser applications. There were not very different palettes in use in different browsers.^{[citation needed]}

"Web-safe" colors had a flaw in that, on systems such as X11 where the palette is shared between applications, smaller color cubes (5×5×5 or 4×4×4) were allocated by browsers—the "web safe" colors would dither on such systems. Different results were obtained by providing an image with a larger range of colors and allowing the browser to quantize the color space if needed, rather than suffer the quality loss of a double quantization.

As of 2011, personal computers typically^[12] have 24-bit (TrueColor) and the use of "web-safe" colors has fallen into practical disuse.

The "web-safe" colors do not all have standard names, but each can be specified by an RGB triplet: each component (red, green, and blue) takes one of the six values from the following table (out of the 256 possible values available for each component in full 24-bit color).

6 shades of each color

Key	Hex	Decimal	Fraction
0	00	0	0
3	33	51	0.2
6	66	102	0.4
9	99	153	0.6
C or (12)	CC	204	0.8
F or (15)	FF	255	1

The following table shows all of the "web-safe" colors. One shortcoming of the web-safe palette is its small range of light colors for webpage backgrounds, whereas the intensities at the low end of the range, such as the two darkest, are similar to each other, making them hard to distinguish.

Color table[edit]

216 web-safe colors

*000*	300	600	900	C00	*F00*
*003*	303	603	903	C03	*F03*
006	306	606	906	C06	F06
009	309	609	909	C09	F09
00C	30C	60C	90C	C0C	F0C
*00F*	30F	60F	90F	C0F	*F0F*
030	330	630	930	C30	F30
033	333	633	933	C33	F33
036	336	636	936	C36	F36
039	339	639	939	C39	F39
03C	33C	63C	93C	C3C	F3C
03F	33F	63F	93F	C3F	F3F
060	360	660	960	C60	F60
063	363	663	963	C63	F63
066	366	666	966	C66	F66
069	369	669	969	C69	F69
06C	36C	66C	96C	C6C	F6C
06F	36F	66F	96F	C6F	F6F
090	390	690	990	C90	F90
093	393	693	993	C93	F93
096	396	696	996	C96	F96
099	399	699	999	C99	F99
09C	39C	69C	99C	C9C	F9C
09F	39F	69F	99F	C9F	F9F
0C0	3C0	6C0	9C0	CC0	FC0
0C3	3C3	6C3	9C3	CC3	FC3
0C6	3C6	6C6	9C6	CC6	FC6
0C9	3C9	6C9	9C9	CC9	FC9
0CC	3CC	6CC	9CC	CCC	FCC
0CF	3CF	6CF	9CF	CCF	FCF
*0F0*	3F0	*6F0*	9F0	CF0	*FF0*
0F3	*3F3*	*6F3*	9F3	CF3	*FF3*
*0F6*	*3F6*	6F6	9F6	*CF6*	*FF6*
0F9	3F9	6F9	9F9	CF9	FF9
*0FC*	*3FC*	6FC	9FC	CFC	FFC
*0FF*	*3FF*	*6FF*	9FF	CFF	*FFF*

each color code listed is a shorthand for the RGB value; for example, code 609 is equivalent to RGB code 102-0-153 or HEX code #660099

Safest web colors[edit]

Designers were encouraged to stick to these 216 "web-safe" colors in their websites because there were a lot of 8-bit color displays when the 216-color palette was developed. David Lehn and Hadley Stern discovered that only 22 of the 216 colors in the web-safe palette are reliably displayed without inconsistent remapping on 16-bit computer displays. They called these 22 colors "the reallysafe palette"; it consists largely of shades of green, yellow, and blue, as can be seen in the table below.^[13]

Safest web colors

	0	3	6	9	C	F
00	*000*					*F00*
03	*003*					*F03*
0F	*00F*					*F0F*
F0	*0F0*		*6F0*			*FF0*
F3		*3F3*	*6F3*			*FF3*
F6	*0F6*	*3F6*			*CF6*	*FF6*[14]
FC	*0FC*	*3FC*
FF	*0FF*	*3FF*	*6FF*			*FFF*

CSS colors[edit]

The Cascading Style Sheets specification defines the same number of named colors as the HTML 4 spec, namely the 16 html colors, and 124 colors from the Netscape X11 color list for a total of 140 names that were recognized by Internet Explorer (IE) 3.0 and Netscape Navigator 3.0.^[15] Blooberry.com notes that Opera 2.1 and Safari 1 also included Netscape's expanded list of 140 color names, but later discovered 14 names not included with Opera 3.5 on Windows 98.^[16]

In CSS 2.1, the color 'orange' (one of the 140) was added to the section with the 16 HTML4 colors as a 17th color.^[17] The CSS3.0 specification did not include orange in the "HTML4 color keywords" section, which was renamed as "Basic color keywords".^[18] In the same reference, the "SVG color keywords" section, was renamed "Extended color keywords", after starting out as "X11 color keywords" in an earlier working draft.^[19] The working draft for the CSS4 color module combines the Basic and Extended sections together in a simple "Named Colors" section.^[20]

Color added in CSS 2.1

Name	Hex (RGB)	Red (RGB)	Green (RGB)	Blue (RGB)	Hue (HSL/HSV)	Satur. (HSL)	Light (HSL)	Satur. (HSV)	Value (HSV)	Alias
orange	#FFA500	100%	65%	0%	39°	100%	50%	100%	100%

CSS 2, SVG and CSS 2.1 allow web authors to use system colors, which are color names whose values are taken from the operating system, picking the operating system's highlighted text color, or the background color for tooltip controls. This enables web authors to style their content in line with the operating system of the user agent.^[21] The CSS3 color module has deprecated the use of system colors in favor of CSS3 UI System Appearance property,^[22][23] which itself was subsequently dropped from CSS3.^[24]

The developing CSS3 specification also introduces HSL color space values to style sheets:^[25]

 /* RGB model */
 p { color: #F00 } /* #rgb */
 p { color: #FF0000 } /* #rrggbb */
 p { color: rgb(255, 0, 0) } /* integer range 0 - 255 */
 p { color: rgb(100%, 0%, 0%) } /* float range 0.0% - 100.0% */

 /* RGB with alpha channel, added to CSS3 */
 p { color: rgba(255, 0, 0, 0.5) } /* 0.5 opacity, semi-transparent */

 /* HSL model, added to CSS3 */
 p { color: hsl(0, 100%, 50%) } /* red */
 p { color: hsl(120, 100%, 50%) } /* green */
 p { color: hsl(120, 100%, 25%) } /* dark green */
 p { color: hsl(120, 100%, 75%) } /* light green */
 p { color: hsl(120, 50%, 50%) } /* pastel green */

 /* HSL model with alpha channel */
 p { color: hsla(120, 100%, 50%, 1) } /* green */
 p { color: hsla(120, 100%, 50%, 0.5) } /* semi-transparent green */
 p { color: hsla(120, 100%, 50%, 0.1) } /* very transparent green */

On 21 June 2014, the CSS WG added the color RebeccaPurple to the Editor's Draft of the CSS4 Colors module, to commemorate Eric Meyer's daughter Rebecca who died on 7 June 2014, her sixth birthday.^[26]

Color added in CSS4 Colors module

Name	Hex (RGB)	Red (RGB)	Green (RGB)	Blue (RGB)	Hue (HSL/HSV)	Satur. (HSL)	Light (HSL)	Satur. (HSV)	Value (HSV)	Alias
RebeccaPurple	#663399	40%	20%	60%	270°	50%	40%	67%	60%

CSS also supports the special color transparent, which represents an alpha value of zero; by default, transparent is rendered as an invisible nominal black: rgba(0, 0, 0, 0)