TextFormat

Limited availability

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

Experimental:This is anexperimental technology
Check theBrowser compatibility table carefully before using this in production.

TheTextFormat interface represents specific formatting that should be applied to a range of text in an editable text region that's attached to anEditContext instance. The text formatting is requested by theInput Method Editor (IME) window that the user is composing text with.

When using one of the default editable regions of the web, such as a<textarea> element, IME composition is handled by the browser and operating system for you. For example, when using Japanese IME in a textarea, on Windows, the following text formats can be applied:

When text is being composed with the keyboard, the typed characters have a thin wavy underline:
When the user selects a suggestion from the list of candidates in the IME window, the text is replaced and is underlined with a thick solid line:

When creating your own custom editable region by using theEditContext API, you need to handle IME composition yourself. You should listen for thetextformatupdate event, which gives you the list of text formats that the IME window wants to apply to the text being composed. You should then update the formatting of the text displayed in your editable region accordingly.

Constructor

TextFormat()Experimental: Returns a newTextFormat instance.

Instance properties

TextFormat.rangeStartRead onlyExperimental: The start position of the text range that needs to be formatted with the given text format.
TextFormat.rangeEndRead onlyExperimental: The end position of the text range that needs to be formatted with the given text format.
TextFormat.underlineStyleRead onlyExperimental: The style of the underline that needs to be applied to the text range that is being formatted.
TextFormat.underlineThicknessRead onlyExperimental: The thickness of the underline that needs to be applied to the text range that is being formatted.

Examples

Using the`textformatupdate` event

In the following example, thetextformatupdate event is used to log the various formats that the IME composition window wants to apply to text ranges in the editable element. Note that the event listener callback in this example is only called when using an IME window to compose text.

html

<div></div>

#editor {  height: 200px;  background: #eeeeee;}

const editorEl = document.getElementById("editor");const editContext = new EditContext(editorEl);editorEl.editContext = editContext;editContext.addEventListener("textformatupdate", (e) => {  // Get the TextFormat instances.  const formats = e.getTextFormats();  // Iterate over the TextFormat instances.  for (const format of formats) {    console.log(      `Applying a ${format.underlineThickness} ${format.underlineStyle} underline between ${format.rangeStart} and ${format.rangeEnd}.`,    );  }});