As i stated in the Comments, the HTMLParser adds it as a CSS Property,
and as already answered by Jasper, it is by Specification.
Implementation
Webkit parses the html in HTMLParser.cpp and if the Parser is inBody it adds the bgColor Attribute as CssColor in HTMLBodyElement.cpp
// Color parsing that matches HTML's "rules for parsing a legacy color value"
void HTMLElement::addHTMLColorToStyle(StylePropertySet* style, CSSPropertyID propertyID, const String& attributeValue)
{
// An empty string doesn't apply a color. (One containing only whitespace does, which is why this check occurs before stripping.)
if (attributeValue.isEmpty())
return;
String colorString = attributeValue.stripWhiteSpace();
// "transparent" doesn't apply a color either.
if (equalIgnoringCase(colorString, "transparent"))
return;
// If the string is a named CSS color or a 3/6-digit hex color, use that.
Color parsedColor(colorString);
if (!parsedColor.isValid())
parsedColor.setRGB(parseColorStringWithCrazyLegacyRules(colorString));
style->setProperty(propertyID, cssValuePool().createColorValue(parsedColor.rgb()));
}
You have good chances to end in this method:
static RGBA32 parseColorStringWithCrazyLegacyRules(const String& colorString)
I think it is to support legacy Colors like this : body bgcolor=ff0000 ( Mozilla Gecko Test ).
- Skip a leading #
- Grab the first 128 characters, replacing non-hex characters with 0.
1120
- Non-BMP characters are replaced with "00" due to them appearing as two "characters" in the String.
- If no digits return Color black
- Split the digits into three components, then search the last 8 digits of each component.
Code of Webkit/HTMLElement.cpp:parseColorStringWithCrazyLegacyRules:
static RGBA32 parseColorStringWithCrazyLegacyRules(const String& colorString)
{
// Per spec, only look at the first 128 digits of the string.
const size_t maxColorLength = 128;
// We'll pad the buffer with two extra 0s later, so reserve two more than the max.
Vector<char, maxColorLength+2> digitBuffer;
size_t i = 0;
// Skip a leading #.
if (colorString[0] == '#')
i = 1;
// Grab the first 128 characters, replacing non-hex characters with 0.
// Non-BMP characters are replaced with "00" due to them appearing as two "characters" in the String.
for (; i < colorString.length() && digitBuffer.size() < maxColorLength; i++) {
if (!isASCIIHexDigit(colorString[i]))
digitBuffer.append('0');
else
digitBuffer.append(colorString[i]);
}
if (!digitBuffer.size())
return Color::black;
// Pad the buffer out to at least the next multiple of three in size.
digitBuffer.append('0');
digitBuffer.append('0');
if (digitBuffer.size() < 6)
return makeRGB(toASCIIHexValue(digitBuffer[0]), toASCIIHexValue(digitBuffer[1]), toASCIIHexValue(digitBuffer[2]));
// Split the digits into three components, then search the last 8 digits of each component.
ASSERT(digitBuffer.size() >= 6);
size_t componentLength = digitBuffer.size() / 3;
size_t componentSearchWindowLength = min<size_t>(componentLength, 8);
size_t redIndex = componentLength - componentSearchWindowLength;
size_t greenIndex = componentLength * 2 - componentSearchWindowLength;
size_t blueIndex = componentLength * 3 - componentSearchWindowLength;
// Skip digits until one of them is non-zero,
// or we've only got two digits left in the component.
while (digitBuffer[redIndex] == '0' && digitBuffer[greenIndex] == '0'
&& digitBuffer[blueIndex] == '0' && (componentLength - redIndex) > 2) {
redIndex++;
greenIndex++;
blueIndex++;
}
ASSERT(redIndex + 1 < componentLength);
ASSERT(greenIndex >= componentLength);
ASSERT(greenIndex + 1 < componentLength * 2);
ASSERT(blueIndex >= componentLength * 2);
ASSERT(blueIndex + 1 < digitBuffer.size());
int redValue = toASCIIHexValue(digitBuffer[redIndex], digitBuffer[redIndex + 1]);
int greenValue = toASCIIHexValue(digitBuffer[greenIndex], digitBuffer[greenIndex + 1]);
int blueValue = toASCIIHexValue(digitBuffer[blueIndex], digitBuffer[blueIndex + 1]);
return makeRGB(redValue, greenValue, blueValue);
}