substr_replace() replaces a copy
of string delimited by the
start and (optionally) length parameters with the
string given in
replacement. The result is returned.
If start is positive,
the replacing will begin at the
start'th offset into
string.
If start is negative,
the replacing will begin at the
start'th character from the end of string.
If length is given and
is positive, it represents the length of the portion of string which is to be replaced.
If it is negative, it represents the number of characters
from the end of string at
which to stop replacing. If it is not given, then it will
default to strlen( string
); i.e. end the replacing at the end of string.
See also str_replace() and
substr().