Handling web elements in any web-based application,iinvolves understanding how to locate and interact with these elements effectively using tools like Selenium WebDriver in Python. The process involves identifying the HTML structure of the web page and then using Selenium’s various methods to locate and manipulate elements like text boxes, buttons, links, dropdowns, etc.

Step-by-Step Guide to Handling Web Elements with Selenium in Python

Step 1: Set Up Your Environment

Ensure you have Python, Selenium, and the necessary WebDriver installed. If you haven’t set it up yet, you can refer to the earlier tutorial on setting up Selenium with Python and using webdriver_manager to handle driver dependencies.

Step 2: Identify Web Elements

To interact with web elements, you first need to identify them. Common methods provided by Selenium to locate elements include:

• find_element_by_id
• find_element_by_name
• find_element_by_xpath
• find_element_by_css_selector
• find_element_by_class_name
• find_element_by_tag_name
• find_element_by_link_text
• find_element_by_partial_link_text

These methods return a WebElement object that you can interact with. For Visma or any other complex application, identifying elements accurately is crucial and might often require using CSS selectors or XPath expressions.

Finding web elements efficiently is a crucial skill for anyone using Selenium for web automation and testing. Web elements can be identified either manually by querying the DOM using tools like Google Chrome’s DevTools or by using automated recorders. Both methods have their uses, but understanding how to manually query the DOM through CSS selectors or XPath expressions gives you more control and precision, which is especially important for complex web applications

Using Google Chrome’s DevTools to Manually Inspect Elements

Google Chrome’s DevTools is an essential tool for web developers and testers. It allows you to inspect the HTML and CSS of a web page and experiment with changes in real-time. Here’s how to use it for finding web elements:

Open DevTools: Right-click on the webpage and select Inspect, or press Ctrl+Shift+I (or Cmd+Opt+I on Mac).

Inspect Elements: Hover over the webpage elements in the browser or use the inspect icon (a mouse cursor and box) in the top-left corner of DevTools to select an element directly on the page.

View and Copy Selectors: In the Elements tab, you can see the HTML structure of the page. Right-click on the highlighted element in the Elements panel, go to Copy, and choose Copy selector for a CSS selector or Copy XPath for an XPath. This gives you a string you can use directly in your Selenium scripts.

Why Learning to Manually Query the DOM is Important

• Precision and Control: Auto-generated selectors from recorders can often be overly specific or not specific enough. Learning to write your own selectors ensures that you target elements in the most efficient way possible.
• Dynamic Elements: Many modern web applications generate dynamic content. IDs, classes, and other attributes might change every time the page loads. Understanding how to select elements based on their relationships and other attributes that do not change is crucial.
• Optimization: Efficient selectors improve the performance of your tests. Simple, direct selectors execute faster than complex, indirect ones. By understanding the DOM structure, you can write more optimized selectors.

Using Recorders for Generating Selectors

Recorders such as Selenium IDE or tools like Katalon Studio can automatically record your interactions with the web and generate the necessary selectors to reproduce these actions in a script. Here’s how you can use these tools:

• Install and Open Recorder: For example, install the Selenium IDE as a browser extension from the Chrome Web Store.
• Record a Session: Click on the Selenium IDE icon and start recording a session. Perform some actions like navigating to a URL, clicking, and entering data.
• Export the Script: Once done, stop recording and review the generated commands, which include the selectors. These can be exported to various programming languages supported by Selenium.

Comparing Manual and Automated Methods

Learning Curve: Manual inspection requires understanding HTML, CSS, and possibly JavaScript, which is more demanding than using a recorder.

Accuracy and Reliability: Manual methods are often more reliable for complex and dynamic content.

Speed: Recorders can quickly generate a full set of scripts that can be a good starting point, especially for straightforward tasks.

In separate lesson it is explained how to find the best elements manually, like you query in SQL

Step 3: Interact with the Elements

Once you’ve identified the elements, you can perform various actions such as:

• Clicking on buttons or links: element.click()
• Entering text in text fields: element.send_keys(“Your text here”)
• Clearing text fields: element.clear()
• Getting text from a web element: text = element.text
• Using drop-down menus: Selenium has a Select class to interact with drop-down menus.

Example: Interacting with Visma

Let’s assume you need to log in to a Visma application(dutch ERP bookkeeping application), navigate to a specific page, and perform some actions. Here’s how you might code it:

from selenium import webdriver
from webdriver_manager.chrome import ChromeDriverManager
from selenium.webdriver.support.ui import WebDriverWait
from selenium.webdriver.support import expected_conditions as EC
from selenium.webdriver.common.by import By

# Setup WebDriver
driver = webdriver.Chrome(ChromeDriverManager().install())

# Open the Visma login page
driver.get("https://login.visma.com")

# Wait for the login elements to be visible and interact with them
username = WebDriverWait(driver, 10).until(
    EC.visibility_of_element_located((By.NAME, "username"))
)
username.send_keys("your_username")

password = driver.find_element_by_name("password")
password.send_keys("your_password")

login_button = driver.find_element_by_id("login-button")
login_button.click()

# Navigate to a specific module
# Assume we wait until a specific element is clickable which navigates to the module
module_button = WebDriverWait(driver, 10).until(
    EC.element_to_be_clickable((By.ID, "module-navigation-button"))
)
module_button.click()

# Perform further actions, like filling out forms or processing data

# Close the browser after your tasks
driver.quit()

Tips for Effective Web Element Handling

• Wait for Elements: Web applications may load content dynamically. Always ensure elements are loaded before interacting with them by using waits (explicit waits are generally preferred for their precision).
• Handle Exceptions: Web automation can fail if elements are not found or interactable. Use try-except blocks to handle these situations gracefully.
• Keep Updated with the UI: If the UI of the application updates (e.g., Google updates its interface), you may need to update your selectors and methods in your scripts.

Conclusion

Automating interactions with web applications like Google involves identifying and manipulating web elements effectively using Selenium WebDriver. This allows for robust automation scripts that can log in, input data, retrieve data, and navigate complex workflows within web applications. Remember, the key to successful automation is understanding the DOM structure of the application and writing resilient code that can handle changes and exceptions.