$re = '/^(
\#[\da-f]{3}
|\#[\da-f]{6}
|rgba\(
((\d{1,2}|1\d\d|2([0-4]\d|5[0-5]))\s*,\s*){2}
((\d{1,2}|1\d\d|2([0-4]\d|5[0-5]))\s*)
(,\s*(0\.\d+|1))
\)
|hsla\(
\s*((\d{1,2}|[1-2]\d{2}|3([0-5]\d|60)))\s*,
\s*((\d{1,2}|100)\s*%)\s*,
\s*((\d{1,2}|100)\s*%)
(,\s*(0\.\d+|1))
\)
|rgb\(
((\d{1,2}|1\d\d|2([0-4]\d|5[0-5]))\s*,\s*){2}
((\d{1,2}|1\d\d|2([0-4]\d|5[0-5]))\s*)
\)
|hsl\(
\s*((\d{1,2}|[1-2]\d{2}|3([0-5]\d|60)))\s*,
\s*((\d{1,2}|100)\s*%)\s*,
\s*((\d{1,2}|100)\s*%)
\)
)$/imx';
$str = '#ffffff
#nothing
#AF12AA
rgba(222, 222, 222)
RgBa(72,73,75)
hsl(0, 100%, 100%)
rgba(1024, 1024, 10)
#ffffff
#ffffffasdf
asdf#ffffff
rgba(170,221,255,0.59)
rgba(170,221,255,0.59)asdf
rgb(0, 0, 0)
asdfrgb(0, 0, 0)
rgb(0, 0, 0)asdf
hsla(208, 56%, 46%, 1)
hsla(208, 56%, 46%, 1)asdf
asdfhsla(208, 56%, 46%, 1)
hsl(208,56%,46%)asdf
asdfhsl(208,56%,46%)';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php