DocumentOrShadowRoot.getSelection()

实验性: 这是一项实验性技术
在将其用于生产之前，请仔细检查浏览器兼容性表格。

The getSelection() property of the DocumentOrShadowRoot interface returns a Selection object representing the range of text selected by the user, or the current position of the caret.

Syntax

var selection = documentOrShadowRootInstance.getSelection()

Parameters

None.

Returns

A Selection object.

Example

function foo() {
    var selObj = document.getSelection();
    alert(selObj);
    var selRange = selObj.getRangeAt(0);
    // do stuff with the range
}

Notes

String representation of the Selection object

In JavaScript, when an object is passed to a function expecting a string (like Window.alert()), 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 results 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:

var selectedText = selObj.toString();
  • selObj is a Selection object.
  • selectedText is a string (Selected text).

HTML inputs provide simpler helper APIs for working with selection (see HTMLInputElement.setSelectionRange()).

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

Specifications

Specification
Selection API
# dom-document-getselection

Browser Compatibility

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