String substr()Limited availability
The substr() method of strings returns part of a string, starting from an index and ending a given number of characters after.
Not yet supported in all major browsers — check the table and provide a fallback.
Discouraged: TC39 included substr() in Annex B of the ECMAScript specification, which covers JavaScript features with "one or more undesirable characteristics and in the absence of legacy usage would be removed."
Browser support
DesktopChrome
1+Supportedsince Dec 11, 2008
Current: 155Edge
12+Supportedsince Jul 29, 2015
Current: 154Firefox
1+Supportedsince Nov 9, 2004
Current: 157Safari
1+Supportedsince Jun 23, 2003
Current: 27MobileChrome Android
18+Supportedsince Jun 27, 2012
Current: 155Firefox Android
4+Supportedsince Mar 29, 2011
Current: 157Safari iOS
1+Supportedsince Jun 29, 2007
Current: 27How to use
Support is still inconsistent across browsers. Use feature detection and test carefully.
Example
Full syntax and examples are on MDN: substr.
Feature detection
JS · check before using
if ("substr" in String || ("prototype" in String && "substr" in String.prototype)) {
// String.substr is available
}