How to check if any Alert exists using Selenium with Java?

Last Updated : 03 Oct, 2024

Checking if an alert exists using Selenium with Java is a common scenario when testing web applications. Alerts are pop-up windows generated by the browser to notify users of important messages, such as errors, warnings, or confirmations. An alert window is a pop-up box that is shown over the webpage to convey error messages using the alert() function of JavaScript. A person might have to check the presence of such alert windows on the webpages for testing purposes.

In this tutorial, we will be using Selenium and Java to check if the alert window is present or not.

Different ways to check for Alert window

Multiple ways are used in which we can confirm the presence of an alert window on the webpage. Let us see these techniques and their working.

Note that before attempting to run these codes, you must either have created a Java project with build tools (Maven/Gradle) or created a simple Java project and download the Selenium JAR files from the internet. Also, you must have respective driver for your browser.

1) Using switchTo().alert() method

Java

import org.openqa.selenium.NoAlertPresentException;
import org.openqa.selenium.WebDriver;
import org.openqa.selenium.chrome.ChromeDriver;

public class App {
    public static void main(String[] args) throws Exception {
        System.setProperty("webdriver.chrome.driver", "C:\\Drivers\\chromedriver.exe");//change the path manualy

        WebDriver driver = new ChromeDriver();

        driver.get("https://globbertrot.github.io/alertpage/");

        if (isAlertPresent(driver)) {
            System.out.println("Alert present");
        } else {
            System.out.println("No alert present");
        }
        driver.quit();
    }
    public static boolean isAlertPresent(WebDriver driver) {
        try {
            driver.switchTo().alert();
            return true;
        } catch (NoAlertPresentException e) {
            return false;
        }
    }
}

Explanation

We have created a method named isAlertPresent() which takes the driver object as an argument.
We are trying to change the context from the webpage to the alert window using switchTo().alert().
If the alert window is not present, then switchTo().alert() throws NoAlertPresentException which we can catch to know alert window is not present.

2) Using UnhandledAlertException exception

Java

import org.openqa.selenium.UnhandledAlertException;
import org.openqa.selenium.WebDriver;
import org.openqa.selenium.chrome.ChromeDriver;

public class App {
    public static void main(String[] args) throws Exception {
        System.setProperty("webdriver.chrome.driver", "C:\\Drivers\\chromedriver.exe");//change the path manualy

        WebDriver driver = new ChromeDriver();

        driver.get("https://globbertrot.github.io/alertpage/");

        if (isAlertPresent(driver)) {
            System.out.println("Alert present");
        } else {
            System.out.println("No alert present");
        }
        driver.quit();
    }
    public static boolean isAlertPresent(WebDriver driver) {
        try {
            driver.getTitle();
            return false;
        } catch (UnhandledAlertException e) {
            return true;
        }
    }
}

Explanation

We have created a method named isAlertPresent() which takes the driver object as an argument.
We are trying to get the title of the webpage. Alternatively, we can perform any action on the webpage apart from getting title.
If an alert is present on the webpage, then while trying to perform the above action, selenium will throw a UnhandledAlertException, suggesting to address the alert before performing any action on the webpage.
We are catching this exception to check the presence of alert window.

3) Using ExpectedConditions.alertIsPresent() method

Java

import org.openqa.selenium.TimeoutException;
import org.openqa.selenium.WebDriver;
import org.openqa.selenium.chrome.ChromeDriver;
import org.openqa.selenium.support.ui.ExpectedConditions;
import org.openqa.selenium.support.ui.WebDriverWait;

import java.time.Duration;

public class App {
    public static void main(String[] args) throws Exception {
        System.setProperty("webdriver.chrome.driver", "C:\\Drivers\\chromedriver.exe");//change the path manualy

        WebDriver driver = new ChromeDriver();

        driver.get("https://globbertrot.github.io/alertpage/");

        if (isAlertPresent(driver)) {
            System.out.println("Alert present");
        } else {
            System.out.println("No alert present");
        }
        driver.quit();
    }
    public static boolean isAlertPresent(WebDriver driver){
        WebDriverWait wait = new WebDriverWait(driver, Duration.ofSeconds(0L));
        try {
            wait.until(ExpectedConditions.alertIsPresent());
            return true;
        } catch (TimeoutException eTO) {
            return false;
        }
    }
}

Explanation

We have created a method named isAlertPresent() which takes the driver object as an argument.
We are creating an explicit wait using WebDriverWait class.
ExpectedConditions is a class containing various pre-defined conditions to be used along with a Wait object.
One such method is alertIsPresent() which checks for the presence of alert window.
Internally it uses switchTo().alert() method.

Output

Conclusion

In conclusion, handling alerts in Selenium using Java is an important skill for testers, as it allows the automation process to seamlessly manage pop-up alerts. By using methods like switchTo().alert(), UnhandledAlertException, or ExpectedConditions.alertIsPresent(), you can efficiently check for and handle alerts during web application testing.

This ensures smoother testing, enabling you to bypass unnecessary interruptions and maintain test integrity.