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Selection: modify() method

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since ⁨January 2020⁩.

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

Syntax

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

Note: Starting in Firefox 5, 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.

Return value

None (undefined).

Examples

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

Specification
Selection API> # dom-selection-modify>

Browser compatibility

	Desktop					Mobile
	Chrome	Edge	Firefox	Opera	Safari	Chrome Android	Firefox for Android	Opera Android	Safari on IOS	Samsung Internet	WebView Android	WebView on iOS
`modify`	1	79	4	15	1.3	18	4	14	1	1.0	4.4	1