HTMLIFrameElement.getCanGoBack() 编辑

Non-standard
This feature is non-standard and is not on a standards track. Do not use it on production sites facing the Web: it will not work for every user. There may also be large incompatibilities between implementations and the behavior may change in the future.

The getCanGoBack() method of the HTMLIFrameElement interface is used to indicate whether it's possible to go back in the navigation history of the browser <iframe>.

Syntax

instanceOfHTMLIframeElement.getCanGoBack()
.then(function(result) { ... });

Returns

A Promise that resolves with a boolean that equals true if the history can be navigated backward or false if not.

Parameters

None.

Example

function canMoveBwd() {
  browser.getCanGoBack().then(function(result) {
    if (result) {
      back.disabled = false;
      console.log("It's possible to navigate
                   the history backward.");
    } else {
      back.disabled = true;
      console.log("It's not possible to navigate
                   the history backward.");
    }
  });
}

Specification

Not part of any specification.

Browser compatibility

Supported since Firefox 47, in chrome code only. Promise-based syntax only since Firefox 65.

Unlikely ever to be supported in other browsers.

See also

• Using the Browser API