Evaluates an expression in the context of the inspected page, and displays the result in the extension sidebar pane.
The expression's execution context is the same as that for inspectedWindow.eval()
.
JSON objects and DOM nodes are displayed as an expandable tree, as in the JSON viewer in Firefox. You can optionally specify a rootTitle
string: this will be displayed as the title of the tree's root.
This is an asynchronous function that returns a Promise
.
Syntax
var evaluating = browser.devtools.panels.setExpression( expression, // string rootTitle // string )
Parameters
expression
string
. The expression to evaluate.rootTitle
Optional- string. The title of the root of the tree in which results are displayed.
Return value
A Promise
that will be fulfilled with no arguments, once the expression has been evaluated.
Browser compatibility
Chrome | Edge | Firefox | Firefox for Android | Opera | |
---|---|---|---|---|---|
Basic support | Yes1 | No | 572 | No | Yes |
1. The expression must evaluate to a JavaScript object or a DOM node, or nothing is shown in the sidebar.
2. The expression must evaluate to an object that can be serialized to JSON, or nothing is shown in the sidebar. In particular, JavaScript cyclic objects and DOM nodes are not supported. See bug 1403130.
The compatibility table in this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request.
Examples
This code creates a sidebar pane that displays the tagName
of the currently selected element:
function onCreated(sidebarPane) { browser.devtools.panels.elements.onSelectionChanged.addListener(() => { const exp = "$0 && $0.tagName"; const title = "Selected Element tagName"; sidebarPane.setExpression(exp, title); }); } browser.devtools.panels.elements.createSidebarPane("My pane").then(onCreated);
This API is based on Chromium's chrome.devtools.panels
API.
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