Web/API/Selection/modify

Non-standard This feature is non-standard and is not on a standards track. Do not use it on production sites facing the Web: it will not work for every user. There may also be large incompatibilities between implementations and the behavior may change in the future.

The Selection.modify() method applies a change to the current selection or cursor position, using simple textual commands.

Syntax

sel.modify(alter, direction, granularity)

Parameters

alter: The type of change to apply. Specify "move" to move the current cursor position or "extend" to extend the current selection.
direction: The direction in which to adjust the current selection. You can specify "forward" or "backward" to adjust in the appropriate direction based on the language at the selection point. If you want to adjust in a specific direction, you can specify "left" or "right".
granularity: The distance to adjust the current selection or cursor position. You can move by "character", "word", "sentence", "line", "paragraph", "lineboundary", "sentenceboundary", "paragraphboundary", or "documentboundary".

Note: Gecko does not implement "sentence", "paragraph", "sentenceboundary", "paragraphboundary", or "documentboundary". WebKit and Blink do.

Note: Starting in Gecko 5.0, the "word" granularity no longer includes the following space, regardless of the default platform behavior. This makes the behavior more consistent, as well as making it work the same way WebKit used to work, but unfortunately they have recently changed their behavior.

Example

This example demonstrates the various granularity options for modifying a selection. Click somewhere inside the example (optionally selecting some text), and then click the button to expand the selection.

HTML

<p>Click somewhere in this example. Then click the button below to expand the selection. Watch what happens!</p>
<p>Et harum quidem rerum facilis est et expedita distinctio. Nam libero tempore, cum soluta nobis est eligendi optio cumque nihil impedit quo minus id quod maxime placeat facere possimus, omnis voluptas assumenda est, omnis dolor repellendus.</p>

<label for="granularity">Granularity:</label>
<select id="granularity">
  <option value="character">Character</option>
  <option value="word">Word</option>
  <option value="sentence">Sentence</option>
  <option value="line">Line</option>
  <option value="paragraph">Paragraph</option>
  <option value="lineboundary">Line Boundary</option>
  <option value="sentenceboundary">Sentence Boundary</option>
  <option value="paragraphboundary">Paragraph Boundary</option>
  <option value="documentboundary">Document Boundary</option>
</select>

<br><br>

<button>Extend selection</button>

JavaScript

let select = document.querySelector('select');
let button = document.querySelector('button');

button.addEventListener('click', modify);

function modify() {
  let selection = window.getSelection();
  selection.modify('extend', 'forward', select.value);
}

Result

Specifications

This method is not part of any specification.

Browser compatibility

Update compatibility data on GitHub

	Desktop						Mobile
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
`modify` Experimental'Non-standard'	Chrome Full support Yes	Edge Full support ≤79	Firefox Full support 4	IE No support No	Opera Full support Yes	Safari Full support Yes	WebView Android Full support Yes	Chrome Android Full support Yes	Firefox Android Full support 4	Opera Android Full support Yes	Safari iOS Full support Yes	Samsung Internet Android Full support Yes
`node` parameter is nullable Experimental'	Chrome Full support Yes	Edge Full support ≤79	Firefox Full support 55	IE No support No	Opera Full support Yes	Safari Full support Yes	WebView Android Full support Yes	Chrome Android Full support Yes	Firefox Android Full support 55	Opera Android Full support Yes	Safari iOS Full support Yes	Samsung Internet Android Full support Yes
`offset` parameter is optional Experimental'	Chrome Full support Yes	Edge Full support ≤79	Firefox Full support 55	IE No support No	Opera Full support Yes	Safari Full support Yes	WebView Android Full support Yes	Chrome Android Full support Yes	Firefox Android Full support 55	Opera Android Full support Yes	Safari iOS Full support Yes	Samsung Internet Android Full support Yes

Legend

Full support: Full support
No support: No support
Experimental. Expect behavior to change in the future.': Experimental. Expect behavior to change in the future.
Non-standard. Expect poor cross-browser support.': Non-standard. Expect poor cross-browser support.