Understanding Stale Element Reference Exception in Selenium

Selenium is a widely used tool for interacting with web elements programmatically in web automation testing. However, one of the common challenges testers face is the Stale Element Reference Exception. This exception occurs when a previously located web element is no longer available in the DOM (Document Object Model), often caused by dynamic page updates or reloading.

Understanding why the Stale Element Reference Exception happens and learning how to handle it effectively is crucial for creating robust and reliable Selenium test scripts.

What is a Stale Element Reference Exception?

A Stale Element Reference Exception in Selenium occurs when a web element that was once found and found and interacted with is no longer valid in the Document Object Model (DOM) that means the element's reference has been become stale or outdated and it can no longer be interacted with the same way.

State Element Reference Exception typically arises in the following situations:

• Page Refresh or Navigation: If a page is refreshed reloaded or navigated away, the previously found elements may no longer exist in the DOM causing the reference to become stale.
• Dynamic Content Updates: The web pages often update the content dynamically using technologies such as AJAX, JavaScript, or DOM manipulations. These updates might replace or remove the elements and make the previously located elements invalid.
• DOM Changes: Any structural changes in DOM like inserting elements, modifying elements, or deleting elements can invalidate the reference to an existing element.

When does the Stale Element Reference Exception occur?

A Stale Element Reference Exception occurs when the element we are trying to interact with is no longer considered valid by the browser's DOM. This typically happens in two main scenarios:

• The HTML web element is no longer present on the webpage: This occurs if an element has been removed or replaced in DOM after an element was referenced. For example, if a page is refreshed or if the JavaScript is dynamically altered the DOM.
• Permanent deletion of referenced element: This happens when an element is entirely removed from DOM, often the result of JavaScript operations or the page transitions.

Why Testing on Real Devices and Browsers important?

Testing on real devices and browsers are the crucial for the ensuring quality and reliability of the web and mobile applications. The following are important for testing:

• Accurate User Experience
• Device-Specific Issues
• Browser-Specific Rendering
• Network Conditions
• Real-world Bugs
• Accurate Geolocation and GPS Testing
• Third-Party Integration
• Testing Edge Cases
• Comprehensive Bug Detection
• Compliance and Certification

How to handle Stale Element Reference Exception in Selenium?

Handling the Stale Element Reference Exception in the Selenium with the help of Java involves the implementing specific strategies. Here we can handle the stale element reference exception.

1. Use WebDriverWait

import org.openqa.selenium.By;
import org.openqa.selenium.WebDriver;
import org.openqa.selenium.WebElement;
import org.openqa.selenium.support.ui.ExpectedConditions;
import org.openqa.selenium.support.ui.WebDriverWait;

public class StaleElementExample {
    public static void main(String[] args) {
        WebDriver driver = // initialize your WebDriver;
        WebDriverWait wait = new WebDriverWait(driver, 10);
        
        WebElement element = wait.until(ExpectedConditions.presenceOfElementLocated(By.id("element_id")));
        element.click();
        
        driver.quit();
    }
}

• WebDriverWait is allowed to the dynamically wait for the element to be present or clickable before performing actions on it. This is help to prevent the Stale Element Reference Exception if an element state is changing.

2. Use the try-catch block

import org.openqa.selenium.By;
import org.openqa.selenium.WebDriver;
import org.openqa.selenium.WebElement;
import org.openqa.selenium.StaleElementReferenceException;

public class StaleElementExample {
    public static void main(String[] args) {
        WebDriver driver = // initialize your WebDriver;
        
        try {
            WebElement element = driver.findElement(By.id("element_id"));
            element.click();
        } catch (StaleElementReferenceException e) {
            // Retry locating and clicking the element
            WebElement element = driver.findElement(By.id("element_id"));
            element.click();
        }
        
        driver.quit();
    }
}

• Wrapping interactions inside the try-catch block can help handle the Stale Element Reference Exception by the catching exception and re-attempting to find and interact with an element.

3. Use Page Object Model (POM)

import org.openqa.selenium.WebDriver;
import org.openqa.selenium.WebElement;
import org.openqa.selenium.support.FindBy;
import org.openqa.selenium.support.PageFactory;

public class SamplePage {
    WebDriver driver;

    @FindBy(id = "element_id")
    WebElement element;

    public SamplePage(WebDriver driver) {
        this.driver = driver;
        PageFactory.initElements(driver, this);
    }

    public void clickElement() {
        element.click();  // Interact with the element at the time of need
    }
}

public class StaleElementExample {
    public static void main(String[] args) {
        WebDriver driver = // initialize your WebDriver;
        SamplePage samplePage = new SamplePage(driver);

        // Now, perform the action
        samplePage.clickElement();

        driver.quit();
    }
}

• In the Page Object Model design pattern, elements are located at the time of the interaction, reducing the chance of the encountering the stale elements. POM helps the manage stale elements by avoiding the long-term storage of the web elements.

4. Refresh the Web Page

import org.openqa.selenium.By;
import org.openqa.selenium.WebDriver;
import org.openqa.selenium.WebElement;

public class StaleElementExample {
    public static void main(String[] args) {
        WebDriver driver = // initialize your WebDriver;

        // Refresh the page before locating the element
        driver.navigate().refresh();

        // Locate and click the element
        WebElement element = driver.findElement(By.id("element_id"));
        element.click();

        driver.quit();
    }
}

• Sometimes refreshing an entire page helps, especially when DOM has the undergone major updates or changes. It reloads the page to ensure that all the elements are fresh, avoiding the stale elements after the significant DOM changes.

Conclusion

In conclusion, the Stale Element Reference Exception in Selenium occurs when a web element becomes outdated due to DOM changes, page reloads, or dynamic content updates. Properly managing this exception by using techniques like WebDriverWait, refreshing web elements, or applying the Page Object Model (POM) can ensure that your Selenium tests are stable and reliable.

Effectively handling stale elements is key to reducing flaky tests and improving the overall reliability of your automation framework, especially when dealing with dynamic web content