(PHP3 >= 3.0.6, PHP4 )

stristr --  Case-insensitive strstr()


string stristr (string haystack, string needle)

Returns all of haystack from the first occurrence of needle to the end. needle and haystack are examined in a case-insensitive manner.

If needle is not found, returns false.

If needle is not a string, it is converted to an integer and applied as the ordinal value of a character.

See also strchr(), strrchr(), substr(), and ereg().