TextFormat: rangeStart property

Limited availability

This feature is not Baseline because it does not work in some of the most widely-used browsers.

Experimental: This is an experimental technology
Check the Browser compatibility table carefully before using this in production.

The rangeStart property of the TextFormat interface indicates the start position of the text range that needs to be formatted with the given text format.

Value

A Number.

Examples

Reading the range of text that needs to be formatted

The following example shows how to use the textformatupdate event's rangeStart and rangeEnd properties to determine the range of text that needs to be formatted. Note that the event listener callback in this example is only called when using an IME window to compose text.

html
<div id="editor"></div>
js
const editorEl = document.getElementById("editor");
const editContext = new EditContext(editorEl);
editorEl.editContext = editContext;

editContext.addEventListener("textformatupdate", (e) => {
  const formats = e.getTextFormats();

  for (const format of formats) {
    console.log(
      `IME wants to apply formatting between ${format.rangeStart} and ${format.rangeEnd}.`,
    );
  }
});

Specifications

Specification
EditContext API
# dom-textformat-rangestart

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
rangeStart
Experimental
Chrome – Full support
Chrome 121 (Release date: 2024-01-23)
footnote Full support
Edge – Full support
Edge 121 (Release date: 2024-01-25)
footnote Full support
Firefox – No support
Firefox
footnote No support
Opera – Full support
Opera 107 (Release date: 2024-02-07)
footnote Full support
Safari – No support
Safari
footnote No support
Chrome Android – Full support
Chrome Android 121 (Release date: 2024-01-23)
footnote Full support
Firefox for Android – No support
Firefox for Android
footnote No support
Opera Android – Full support
Opera Android 81 (Release date: 2024-03-14)
footnote Full support
Safari on iOS – No support
Safari on iOS
footnote No support
Samsung Internet – Full support
Samsung Internet 25 (Release date: 2024-04-24)
footnote Full support
WebView Android – Full support
WebView Android 121 (Release date: 2024-01-23)
footnote Full support
WebView on iOS – No support
WebView on iOS
footnote No support

Legend

Tip: you can click/tap on a cell for more information.

Full support
Full support
No support
No support
Experimental. Expect behavior to change in the future.

See also