Untested:
if (preg_match('/^http:\/\/[^\.\s]+\.[^\s]+\/$/i', $string))
// valid string
else
// invalid string
Should match a string beginning with 'http://', followed by one or more
characters that are no dots or whitespace, followed by a dot, followed >by one or more characters that are not whitespace, and terminated with >a slash. The terminating 'i' makes the search case insensitive.
I've also been looking for this information. Can you please point me to a list of those string codes? My search for them in the documentation has been fruitless.
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