How do you handle random alerts or pop-ups that appear unexpectedly in Selenium?

Answer

Handling Random/Unexpected Alerts in Selenium

Some applications show alerts randomly — cookie consent banners, session warnings, or promotional pop-ups. These break tests if not handled.

Dismiss Alert If Present (Try-Catch Pattern)

Java

public void dismissAlertIfPresent() {
    try {
        Alert alert = driver.switchTo().alert();
        System.out.println("Alert text: " + alert.getText());
        alert.dismiss(); // or alert.accept()
    } catch (NoAlertPresentException e) {
        // No alert — that''s fine, continue
    }
}

// Call before any critical action
dismissAlertIfPresent();
driver.findElement(By.id("checkoutBtn")).click();

Wait for Alert and Handle

Java

WebDriverWait wait = new WebDriverWait(driver, Duration.ofSeconds(5));
try {
    Alert alert = wait.until(ExpectedConditions.alertIsPresent());
    alert.accept();
} catch (TimeoutException e) {
    // No alert appeared within 5 seconds
}

Handle CSS/Modal Pop-ups (Not JS Alerts)

Java

// Check if modal is visible and close it
try {
    WebElement closeBtn = driver.findElement(By.cssSelector(".modal .close-btn"));
    if (closeBtn.isDisplayed()) {
        closeBtn.click();
    }
} catch (NoSuchElementException e) {
    // Modal not present
}

TestNG Listener — Handle Alerts on Every Failure

Java

@Override
public void onTestFailure(ITestResult result) {
    try {
        driver.switchTo().alert().dismiss();
    } catch (NoAlertPresentException ignored) {}
    // Then take screenshot
}

Types of Pop-ups and How to Handle

Pop-up Type	Selenium Approach
JS `alert()`	`driver.switchTo().alert().accept()`
JS `confirm()`	`.accept()` or `.dismiss()`
JS `prompt()`	`.sendKeys("text")` then `.accept()`
CSS Modal	Find and click close button
Browser auth dialog	Pass credentials in URL
Cookie banner	Click "Accept" button