Implementation:Microsoft Playwright BidiExecutionContext

Knowledge Sources	Microsoft_Playwright
Domains	BiDi, JavaScript
Last Updated	2026-02-12 00:00 GMT

Overview

Concrete tool for evaluating JavaScript expressions and calling functions within a BiDi browser execution context provided by the Playwright library.

Description

The `BidiExecutionContext` class implements the `js.ExecutionContextDelegate` interface for the WebDriver BiDi protocol. It wraps a `BidiSession` and a target (either a browsing context with optional sandbox, or a realm). The class provides `rawEvaluateJSON` for simple expression evaluation returning JSON values, `rawEvaluateHandle` for expressions returning remote object handles, and `evaluateWithArguments` for calling functions with serialized arguments via `script.callFunction`. It uses `BidiSerializer` for argument serialization and `deserializeBidiValue` for result deserialization.

Usage

Use BidiExecutionContext when Playwright needs to evaluate JavaScript in a BiDi-connected browser page, frame, or worker context.

Code Reference

Source Location

• Repository: Microsoft_Playwright
• File: packages/playwright-core/src/server/bidi/bidiExecutionContext.ts

Signature

export class BidiExecutionContext implements js.ExecutionContextDelegate {
  private readonly _session: BidiSession;
  readonly _target: bidi.Script.Target;
  constructor(session: BidiSession, realmInfo: bidi.Script.RealmInfo);
  async rawEvaluateJSON(expression: string): Promise<any>;
  async rawEvaluateHandle(context: js.ExecutionContext, expression: string): Promise<js.JSHandle>;
  async evaluateWithArguments(expression: string, returnByValue: boolean, utilityScript: js.JSHandle, values: any[], handles: js.JSHandle[]): Promise<any>;
}

Import

import { BidiExecutionContext } from '../server/bidi/bidiExecutionContext';

I/O Contract

Inputs

Name	Type	Required	Description
session	BidiSession	Yes	The BiDi session used to send commands
realmInfo	bidi.Script.RealmInfo	Yes	Realm information identifying the execution context
expression	string	Yes	JavaScript expression or function body to evaluate
values	any[]	No	Serialized argument values for function calls
handles	js.JSHandle[]	No	Remote object handle arguments for function calls

Outputs

Name	Type	Description
result	any	Deserialized evaluation result value
handle	js.JSHandle	Remote handle to the evaluation result

Usage Examples

import { BidiExecutionContext } from '../server/bidi/bidiExecutionContext';

const execContext = new BidiExecutionContext(bidiSession, realmInfo);
const title = await execContext.rawEvaluateJSON('document.title');
const handle = await execContext.rawEvaluateHandle(context, 'document.body');

Related Pages

• Environment:Microsoft_Playwright_Node_Runtime_Environment