diff --git a/src/debug/debugController.ts b/src/debug/debugController.ts
index 1a8286a206ab6..156bd6bb922f3 100644
--- a/src/debug/debugController.ts
+++ b/src/debug/debugController.ts
@@ -16,10 +16,8 @@
 
 import { BrowserContext } from '../server/browserContext';
 import * as frames from '../server/frames';
-import * as js from '../server/javascript';
 import { Page } from '../server/page';
 import { InstrumentingAgent } from '../server/instrumentation';
-import type DebugScript from './injected/debugScript';
 import { Progress } from '../server/progress';
 import { isDebugMode } from '../utils/utils';
 import * as debugScriptSource from '../generated/debugScriptSource';
@@ -33,12 +31,7 @@ export class DebugController implements InstrumentingAgent {
       if ((mainContext as any)[debugScriptSymbol])
         return;
       (mainContext as any)[debugScriptSymbol] = true;
-      const objectId = await mainContext._delegate.rawEvaluate(`new (${debugScriptSource.source})()`);
-      const debugScript = new js.JSHandle(mainContext, 'object', objectId) as js.JSHandle<DebugScript>;
-      const injectedScript = await mainContext.injectedScript();
-      await debugScript.evaluate((debugScript, injectedScript) => {
-        debugScript.initialize(injectedScript, { console: true });
-      }, injectedScript);
+      await mainContext.extendInjectedScript(debugScriptSource.source);
     } catch (e) {
     }
   }
diff --git a/src/debug/injected/debugScript.ts b/src/debug/injected/debugScript.ts
index d0aaf899b3efd..52aac81fa04c1 100644
--- a/src/debug/injected/debugScript.ts
+++ b/src/debug/injected/debugScript.ts
@@ -19,9 +19,7 @@ import type InjectedScript from '../../server/injected/injectedScript';
 
 export default class DebugScript {
   consoleAPI: ConsoleAPI | undefined;
-
-  initialize(injectedScript: InjectedScript, options: { console?: boolean }) {
-    if (options.console)
-      this.consoleAPI = new ConsoleAPI(injectedScript);
+  constructor(injectedScript: InjectedScript) {
+    this.consoleAPI = new ConsoleAPI(injectedScript);
   }
 }
diff --git a/src/server/dom.ts b/src/server/dom.ts
index 766ebdddd46b6..5f2b55c33a7e8 100644
--- a/src/server/dom.ts
+++ b/src/server/dom.ts
@@ -90,6 +90,13 @@ export class FrameExecutionContext extends js.ExecutionContext {
     return this._injectedScriptPromise;
   }
 
+  async extendInjectedScript(source: string, params?: any) {
+    const injectedScriptHandle = await this.injectedScript();
+    return injectedScriptHandle.evaluate((injectedScript, {source, params}) => {
+      return injectedScript.extend(source, params);
+    }, { source, params });
+  }
+
   async doSlowMo() {
     return this.frame._page._doSlowMo();
   }
diff --git a/src/server/injected/injectedScript.ts b/src/server/injected/injectedScript.ts
index e26d690b78c6d..df10789f6a168 100644
--- a/src/server/injected/injectedScript.ts
+++ b/src/server/injected/injectedScript.ts
@@ -19,7 +19,7 @@ import { createCSSEngine } from './cssSelectorEngine';
 import { SelectorEngine, SelectorRoot } from './selectorEngine';
 import { createTextSelector } from './textSelectorEngine';
 import { XPathEngine } from './xpathSelectorEngine';
-import { ParsedSelector } from '../common/selectorParser';
+import { ParsedSelector, parseSelector } from '../common/selectorParser';
 import { FatalDOMError } from '../common/domErrors';
 
 type Predicate<T> = (progress: InjectedScriptProgress, continuePolling: symbol) => T | symbol;
@@ -63,6 +63,10 @@ export class InjectedScript {
       this.engines.set(name, engine);
   }
 
+  parseSelector(selector: string): ParsedSelector {
+    return parseSelector(selector);
+  }
+
   querySelector(selector: ParsedSelector, root: Node): Element | undefined {
     if (!(root as any)['querySelector'])
       throw new Error('Node is not queryable.');
@@ -108,6 +112,11 @@ export class InjectedScript {
     return candidates.filter(e => !!this._querySelectorRecursively(e, partial, 0));
   }
 
+  extend(source: string, params: any): any {
+    const constrFunction = global.eval(source);
+    return new constrFunction(this, params);
+  }
+
   isVisible(element: Element): boolean {
     // Note: this logic should be similar to waitForDisplayedAtStablePosition() to avoid surprises.
     if (!element.ownerDocument || !element.ownerDocument.defaultView)