JavaScript String substr()
Examples
Extract a substring from text:
let text = "Hello world!";
let result = text.substr(1, 4);
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let result = text.substr(1, 4);
Start at position 2:
let result = text.substr(2);
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More examples below.
Description
The substr() method extracts a part of a string.
The substr() method begins at a specified position, and returns a specified number of characters.
The substr() method does not change the original string.
To extract characters from the end of the string, use a negative start position.
Warning
The substr() method is removed (deprecated) in the latest JavaScript standard.
Use substring() or slice() instead.
Syntax
string.substr(start, length)
Parameters
Parameter
Description
start
Required.
The start position.
First character is at index 0.
If start is greater than the length, substr() returns "".
If start is negative, substr() counts from the end of the string.
The start position.
First character is at index 0.
If start is greater than the length, substr() returns "".
If start is negative, substr() counts from the end of the string.
length
Optional.
The number of characters to extract.
If omitted, it extracts the rest of the string
The number of characters to extract.
If omitted, it extracts the rest of the string
Return Value
Type
Description
A string A string containing the extracted part.
If length is 0 or negative, an empty string is returned.
If length is 0 or negative, an empty string is returned.
More Examples
Only the first:
let result = text.substr(0, 1);
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Only the last:
let result = text.substr(text.length-1, 1);
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The last 6:
let result = text.substr(-6, 6);
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Browser Support
substr() is an ECMAScript1 (JavaScript 1997) feature.
It is supported in all browsers:
| Chrome | Edge | Firefox | Safari | Opera |