devtools.panels.ElementsPanel.setExpression()
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
js
let 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
BCD tables only load in the browser
Examples
This code creates a sidebar pane that displays the tagName
of the currently selected element:
js
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);
Note: This API is based on Chromium's chrome.devtools.panels
API.