JavaScript substring () method

Definition and usage

The substring () method is used to extract the character of a string intermediary between two specified subscripts.

Grammar

stringobject. substring (start,stop)

Parameters	Description
Start	Necessary. A nonnegative integer that specifies the position of the first character of the substring to be extracted in the stringobject.
Stop	Optional. A nonnegative integer that is 1 more than the last character of the substring to extract in Stringobject. If this argument is omitted, the returned substring continues until the end of the string.

return value

A new string value that contains a substring of Stringobject whose contents are all characters from start to stop-1, with a length of stop minus C12>start.

Description

The substring returned by the substring () method includes the character at start , but does not include the character at the stop .

If the argument start is equal to stop , the method returns an empty string (that is, a string of length 0). If start is larger than stop , the method swaps both parameters before extracting the substring.

Hints and Notes

Important: Unlike the slice () and substr () methods, substring () does not accept negative parameters.

Example 1

In this example, we will use SUBSTRING () to extract some characters from the string:

<script type= "Text/javascript" >var str= "Hello world!" document.write ( str.substring(3) ) </script>

Output:

Lo world!

Try it yourself.

Example 2

In this example, we will use SUBSTRING () to extract some characters from the string:

<script type= "Text/javascript" >var str= "Hello world!" document.write ( str.substring(3,7) ) </script>

Output:

Lo W

JavaScript substring () method