JavaScript Navigator webdriver Property

What You’ll Learn

navigator.webdriver is a Baseline boolean on Navigator. It tells the page whether the browser is controlled by WebDriver automation. Learn when it is true, how to branch for tests, five examples, and what it is not for.

Introduction

Tools like Selenium, Playwright (when configured with WebDriver), and other automation stacks drive a real browser without a human clicking. Pages sometimes need a different path during those runs — skip animations, show debug banners, or avoid prompts that block headless tests.

navigator.webdriver is the standard cooperation signal: cooperating browsers set it to true when they are controlled by automation.

Understanding the webdriver Property

Think of navigator.webdriver as a simple yes/no light: “Is this session driven by WebDriver-style automation?”

• Read-only boolean on Navigator.
• Typically false when you open the site yourself.
• true in automated Chrome / Firefox under the flags MDN documents.
• Useful for alternate test / CI code paths.
• Not a substitute for real security, rate limits, or CAPTCHA where needed.

When MDN says it is true

• Chrome — --enable-automation or --headless, or --remote-debugging-port with port 0.
• Firefox — marionette.enabled preference or --marionette flag.

📝 Syntax

General form of the property:

navigator.webdriver

Value

• A boolean — true when controlled by automation; otherwise usually false.

Common patterns

console.log(navigator.webdriver); // false in a normal browsing session

if (navigator.webdriver) {
  // Automated run — e.g. skip long animations, enable test hooks
  console.log("Running under WebDriver automation");
} else {
  console.log("Interactive (human) session");
}

Examples Gallery

Examples follow MDN navigator.webdriver behavior. Prefer Try It Yourself — in a normal browser window you should usually see false.

console.log(navigator.webdriver);

false
(true under WebDriver / documented automation flags)

const lines = [
  "value: " + navigator.webdriver,
  "typeof: " + typeof navigator.webdriver
];
console.log(lines.join("\n"));

value: false
typeof: boolean

function playIntro() {
  if (navigator.webdriver) {
    return "Skip intro animation (WebDriver session)";
  }
  return "Play full intro animation (interactive session)";
}

console.log(playIntro());

Play full intro animation (interactive session)

const label = navigator.webdriver
  ? "automation"
  : "interactive";

const lines = [
  "session: " + label,
  "webdriver: " + navigator.webdriver
];
console.log(lines.join("\n"));

session: interactive
webdriver: false

const hooks = {};

if (navigator.webdriver) {
  hooks.seedDemoData = function () {
    return "Demo data seeded for automated tests";
  };
}

if (hooks.seedDemoData) {
  console.log(hooks.seedDemoData());
} else {
  console.log("No automation hooks (interactive session)");
}

No automation hooks (interactive session)

🚀 Common Use Cases

• Faster CI runs — disable long intros, tours, or decorative delays.
• Stable end-to-end tests — avoid flaky waits tied to animations.
• Debug banners — show “Automated session” in staging when WebDriver is on.
• Support logs — record whether a report came from automation.
• Not sole bot defense — combine with server checks if security matters.

📝 Notes

• Baseline Widely available (MDN, since May 2018).
• Not Deprecated, Experimental, or Non-standard — no status banner required.
• Read-only boolean: automation signal for cooperating WebDriver sessions.
• Chrome / Firefox set true under the flags MDN documents.
• Related: userAgent, userAgentData, windowControlsOverlay, Window.

💡 Best Practices