In Selenium’s JavaScript binding, mark your test or helper async and await WebDriver calls and waits that return promises. Use executeAsyncScript only when you need JavaScript running inside the browser page to perform asynchronous work and return a result through Selenium’s callback. Those are different kinds of waiting: one is in your Node.js test code; the other is in the page context.
Await WebDriver commands in JavaScript test code
WebDriver operations in Selenium’s JavaScript binding return promises. Put the sequence in an async function and await each operation whose result the next step depends on. This representative pattern builds a Chrome session, opens a page, waits for a button to exist, clicks it, waits for the title to change, and quits the browser even if a step fails:
const { Builder, By, until } = require('selenium-webdriver');
async function example() {
const driver = await new Builder().forBrowser('chrome').build();
try {
await driver.get('https://example.test');
const button = await driver.wait(
until.elementLocated(By.id('continue')),
10_000
);
await button.click();
await driver.wait(until.titleIs('Next step'), 10_000);
} finally {
await driver.quit();
}
}
example().catch(error => {
console.error(error);
process.exitCode = 1;
});The example assumes the selenium-webdriver package is installed, Chrome is available to the WebDriver setup, and the page has the specified element and title behavior. The waits are capped at 10 seconds; if a condition is not met, the wait rejects and the error reaches the caller. The finally block ensures the session is asked to close on either success or failure.
await driver.get(...) waits for the WebDriver command’s promise to resolve. It does not make JavaScript in the page asynchronous or, by itself, establish that a particular application component is ready.
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Wait for application state instead of sleeping
When the next test step depends on a UI state, use driver.wait(condition, timeout) with a condition that expresses that state. Selenium’s JavaScript wait API repeatedly evaluates conditions and also accepts promise-like conditions. For example, until.elementLocated(By.id('continue')) waits for an element to be located; it does not necessarily mean the element is visible, enabled, or safe to click. Choose a condition that matches the next action, or wait for the relevant state explicitly.
A fixed delay such as await driver.sleep(2000) consumes that time even when the page is ready sooner, and still does not prove readiness if the page takes longer. A condition-based wait ties the test to the event it needs and fails at a defined timeout if it never occurs.
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Run asynchronous JavaScript inside the page
Use driver.executeAsyncScript when the test needs to initiate or observe asynchronous work in the selected browser frame and return a value to Node.js. Selenium appends an injected completion callback as the final argument to the page function. The page script must call it to signal completion:
const value = await driver.executeAsyncScript(function () {
const done = arguments[arguments.length - 1];
fetch('/api/status')
.then(response => response.json())
.then(data => done(data.status))
.catch(error => done({ error: String(error) }));
});This is a callback contract, not a promise-return contract: do not assume Selenium will wait simply because the page function returns a Promise. If the callback is never invoked, the command remains pending until the script timeout. The supplied function is serialized for execution in the page, so it cannot rely on lexical variables from the Node.js test process. Pass data into the page through supported script arguments, or make the page function self-contained.
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For many synchronization problems, a WebDriver wait for a visible or otherwise meaningful UI condition is clearer than starting a page-side fetch. Use executeAsyncScript when the browser-context operation itself and its returned value are what the test needs.
Choose the right kind of wait
| Need | Use | How it completes |
|---|---|---|
| Sequence commands in the JavaScript WebDriver binding | async function with await on driver calls |
The WebDriver promise resolves or rejects. |
| Wait until a UI condition becomes true | driver.wait(condition, timeout) |
The condition resolves truthy, or the wait times out. |
| Run asynchronous JavaScript in the selected page frame and return a value | driver.executeAsyncScript(...) |
The page script calls Selenium’s injected callback. |
Set a bounded script timeout
The Selenium JavaScript WebDriver implementation documentation accessed in 2026 documents a default script timeout of 30000 milliseconds. Defaults may depend on the installed binding and version, so check the API for the version in your project rather than treating that value as universal. Set a session script timeout appropriate to the page-side operation, and keep it bounded so a missing callback does not leave the test waiting indefinitely.
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Timeout configuration is binding-specific. Python uses driver.set_script_timeout(seconds) with execute_async_script; Java uses the WebDriver timeout API with JavascriptExecutor.executeAsyncScript. Do not copy those method names or their syntax into JavaScript tests.
Troubleshoot common async and await failures
- A test moves on before a WebDriver operation finishes: Make the helper or test function
asyncand await the relevant WebDriver promise. Returning a promise from a helper is also valid if its caller awaits it. executeAsyncScripthangs until timeout: Check every success and error path in the page function and ensure each calls the injected callback exactly once. A rejected fetch or a parsing error that is not handled can otherwise leave completion unreported.- The page function cannot read a Node.js variable: The function runs in the page after serialization; Node lexical scope is not available there. Make it self-contained or pass needed values using the script-execution arguments supported by WebDriver.
- The test clicks too early after locating an element: Location alone may not establish visibility or enabled state. Wait for the specific state required by the action.
- A fixed sleep is flaky or slow: Replace it with a condition-based wait for the application state the test actually needs, with an explicit timeout.
- A timeout example from another language does not work: Confirm the binding. JavaScript, Python, and Java expose different method names and configuration patterns.
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