Name
String.substring( ) — return a substring of a string
Availability
JavaScript 1.0; JScript 1.0, ECMAScript v1
Synopsis
string
.substring(from
,to
)
Arguments
-
from
An integer that specifies the position within
string
of the first character of the desired substring.-
to
An optional integer that is one greater than the position of the last character of the desired substring. If this argument is omitted, the returned substring runs to the end of the string.
Returns
A new string, of length to
-from
, which contains a
substring of string
. The new string
contains characters copied from positions
from
to to
-1
of string
.
Description
String.substring( )
returns a substring of
string
consisting of the characters
between positions from
and
to
. The character at position
from
is included, but the character at
position to
is not included.
If from
equals
to
, this method returns an empty (length
0) string. If from
is greater than
to
, this method first swaps the two
arguments and then returns the substring between them.
It is important to remember that the character at position
from
is included in the substring but that
the character at position to
is not
included in the substring. While this may seem arbitrary or
counterintuitive, a notable feature of this system is that the length
of the returned substring is always equal to
to
-from
.
Note that String.slice( )
and the nonstandard
String.substr( )
can also be used to extract
substrings from a string.
Bugs
In Netscape’s implementations of JavaScript, ...
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