This feature has been removed from the Web standards. Though some browsers may still support it, it is in the process of being dropped. Do not use it in old or new projects. Pages or Web apps using it may break at any time.


The sub() method creates a <sub> HTML element that causes a string to be displayed as subscript.




The sub() method embeds a string in a <sub> tag: "<sub>str</sub>".


Example: Using sub() and sup() methods

The following example uses the sub() and sup() methods to format a string:

var superText = 'superscript';
var subText = 'subscript';

document.write('This is what a ' + superText.sup() + ' looks like.');
document.write('This is what a ' + subText.sub() + ' looks like.');

This example produces the same output as the following HTML:

This is what a <sup>superscript</sup> looks like.
This is what a <sub>subscript</sub> looks like.


Specification Status Comment
ECMAScript 6 (ECMA-262)
The definition of 'String.prototype.sub' in that specification.
Release Candidate Initial definition. Implemented in JavaScript 1.0.
Defined in the (normative) Annex B for Additional ECMAScript Features for Web Browsers.

Browser compatibility

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari
Basic support (Yes) 1.0 (1.7 or earlier) (Yes) (Yes) (Yes)
Feature Android Chrome for Android Firefox Mobile (Gecko) IE Mobile Opera Mobile Safari Mobile
Basic support (Yes) (Yes) 1.0 (1.0) (Yes) (Yes) (Yes)

See also

Document Tags and Contributors

Last updated by: Sevenspade,