JavaScript (ES2026) reference · String Methods

JavaScript String substring() Method

Return the part of a string between two indexes. Unlike slice(), negative values become 0 and swapped arguments are reordered.

JavaScript (ES2026) Since ES1

Create a free account to save this page, take notes and track your progress. Sign in

Syntax

string.substring(start, end)

Parameter	Description
`start`	Start index.
`end` optional	Index to stop before. Default: `string.length`

A new string.

Arguments are reorderedTry it yourself

const s = "JavaScript";
console.log(s.substring(0, 4), s.substring(4, 0));

Output

Java Java

Negative values: substring() vs slice()Try it yourself

const s = "JavaScript";
console.log(s.substring(-3), "|", s.slice(-3));

Output

JavaScript | ipt

Version	Change
JavaScript ES1	Added

string.slice() · Extract part of a string between two indexes; negative indexes count from the end.
JavaScript Strings · tutorial
JavaScript String Methods · tutorial