The Window.getSelection() method returns a Selection object representing the range of text selected by the user or the current position of the caret.

None.

A Selection object.

When cast to string, either by appending an empty string ("") or using Selection.toString(), this object returns the text selected.

When called on an <iframe> that is not displayed (e.g., where display: none is set) Firefox will return null, whereas other browsers will return a Selection object with Selection.type set to None.

In JavaScript, when an object is passed to a function expecting a string (like window.alert() or document.write()), the object's toString() method is called and the returned value is passed to the function. This can make the object appear to be a string when used with other functions when it is really an object with properties and methods.

In the above example, selObj.toString() is automatically called when it is passed to window.alert(). However, attempting to use a JavaScript String property or method such as length or substr directly on a Selection object will result in an error if it does not have that property or method and may return unexpected results if it does. To use a Selection object as a string, call its toString() method directly:

const selectedText = selObj.toString();

• selObj is a Selection object.
• selectedText is a string (Selected text).

You can call Document.getSelection(), which works identically to Window.getSelection().

It is worth noting that currently getSelection() doesn't work on the content of <textarea> and <input> elements in Firefox and Edge (Legacy). HTMLInputElement.setSelectionRange() or the selectionStart and selectionEnd properties could be used to work around this.

Notice also the difference between selection and focus. Document.activeElement returns the focused element.

• Selection API
• Selection
• Range
• Document.getSelection()
• HTMLInputElement.setSelectionRange()