The Window.frameElement property returns the element (such as <iframe> or <object>) in which the window is embedded. 
 The Window.frameElement property returns the element (such as <iframe> or <object>) in which the window is embedded. 
 The element which the window is embedded into. If the window isn't embedded into another document, or if the document into which it's embedded has a different origin, the value is null instead. 
js
const frameEl = window.frameElement; // If we're embedded, change the containing element's URL to 'https://mozilla.org/' if (frameEl) { frameEl.src = "https://mozilla.org/"; }
| Specification | 
|---|
| HTML Standard  # dom-frameelement-dev  | 
| Desktop | Mobile | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Chrome | Edge | Firefox | Internet Explorer | Opera | Safari | WebView Android | Chrome Android | Firefox for Android | Opera Android | Safari on IOS | Samsung Internet | |
frameElement | 
1 | 12 | 1 | 5.5 | ≤12.1 | 3 | 4.4 | 18 | 4 | ≤12.1 | 1 | 1.0 | 
window.frames returns an array-like object, listing the direct sub-frames of the current window. window.parent returns the parent window, which is the window containing the frameElement of the child window. 
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    https://developer.mozilla.org/en-US/docs/Web/API/Window/frameElement