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Other References

CSSStyleDeclaration JS Conversion


JavaScript String substr() Method

Example

Extract parts of a string:

var str = "Hello world!";
var res = str.substr(1, 4);
Try it Yourself »

More "Try it Yourself" examples below.


Definition and Usage

The substr() method extracts parts of a string, beginning at the character at the specified position, and returns the specified number of characters.

Tip: To extract characters from the end of the string, use a negative start number (This does not work in IE 8 and earlier).

Note: The substr() method does not change the original string.


Browser Support

Method
substr() Yes Yes Yes Yes Yes

Syntax

string.substr(start, length)

Parameter Values

Parameter Description
start Required. The position where to start the extraction. First character is at index 0.

If start is positive and greater than, or equal, to the length of the string, substr() returns an empty string.

If start is negative, substr() uses it as a character index from the end of the string.

If start is negative or larger than the length of the string, start is set to 0
length Optional. The number of characters to extract. If omitted, it extracts the rest of the string


Technical Details

Return Value: A new String, containing the extracted part of the text. If length is 0 or negative, an empty string is returned
JavaScript Version: ECMAScript 1

More Examples

Example

Begin the extraction at position 2, and extract the rest of the string:

var str = "Hello world!";
var res = str.substr(2);
Try it Yourself »

Example

Extract only the first character:

var str = "Hello world!";
var res = str.substr(0, 1);
Try it Yourself »

Example

Extract only the last character:

var str = "Hello world!";
var res = str.substr(11, 1);
Try it Yourself »