XPath functions (contains, starts-with) in Selenium Java

Introduction

XPath functions like contains and starts-with help find elements on a webpage when exact matches are hard to get. They make locating elements easier and more flexible.

When the element's attribute value changes slightly but has a common part.

When you want to find a button or link that starts with certain text.

When the full text or attribute is long but you know a unique part inside it.

When the webpage uses dynamic IDs or classes that partially stay the same.

When you want to avoid brittle tests that break if exact text changes.

Syntax

Selenium Java

//*[contains(@attribute, 'value')]
//*[starts-with(@attribute, 'value')]

contains() checks if an attribute or text includes a substring anywhere.

starts-with() checks if an attribute or text begins with a substring.

Examples

Finds any input element whose id attribute contains the word 'user'.

Selenium Java

//input[contains(@id, 'user')]

Finds any button element whose visible text starts with 'Log', like 'Login' or 'Logout'.

Selenium Java

//button[starts-with(text(), 'Log')]

Finds any link (a) whose href attribute contains 'contact'.

Selenium Java

//a[contains(@href, 'contact')]

Sample Program

This test opens a login page, finds the username input using contains() on the id, and finds the login button using starts-with() on the button text. It then types a username and clicks the button.

Selenium Java

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

public class XPathFunctionsTest {
    public static void main(String[] args) {
        System.setProperty("webdriver.chrome.driver", "path/to/chromedriver");
        WebDriver driver = new ChromeDriver();
        try {
            driver.get("https://example.com/login");

            // Using contains() to find username input
            WebElement username = driver.findElement(By.xpath("//input[contains(@id, 'user')]");
            username.sendKeys("testuser");

            // Using starts-with() to find login button
            WebElement loginButton = driver.findElement(By.xpath("//button[starts-with(text(), 'Log')]");
            loginButton.click();

            System.out.println("Test passed: Elements found and actions performed.");
        } catch (Exception e) {
            System.out.println("Test failed: " + e.getMessage());
        } finally {
            driver.quit();
        }
    }
}

Important Notes

Always check the webpage source to find stable parts of attributes or text for these functions.

Using these functions makes tests less fragile when small changes happen in the UI.

Be careful: too broad use of contains() can match multiple elements, causing errors.

Summary

contains() finds elements with attribute or text containing a substring.

starts-with() finds elements with attribute or text starting with a substring.

These functions help write flexible and reliable element locators in Selenium tests.

Practice

1. Which XPath function would you use to locate elements whose attribute contains a specific substring anywhere within it?

easy

A. starts-with()

B. ends-with()

C. contains()

D. equals()

Solution

1. Step 1: Understand the purpose of contains()

   The contains() function checks if an attribute or text contains a given substring anywhere inside it.

2. Step 2: Compare with other functions

   starts-with() checks only the beginning, ends-with() is not standard XPath 1.0, and equals() is not an XPath function.

3. Final Answer:

   contains() -> Option C

4. Quick Check:

   Substring anywhere = contains() [OK]

Hint: Use contains() for substring anywhere inside attribute [OK]

Common Mistakes:

• Confusing contains() with starts-with()
• Using ends-with() which is not standard XPath 1.0
• Trying to use equals() as XPath function

2. Which of the following is the correct XPath syntax to find a button element whose id attribute starts with "submit"?

easy

A. //button[contains(@id, 'submit')]

B. //button[@id*='submit']

C. //button[@id^='submit']

D. //button[starts-with(@id, 'submit')]

Solution

1. Step 1: Identify the correct XPath function for 'starts with'

   The function starts-with() is used to check if an attribute starts with a substring.

2. Step 2: Check syntax correctness

   //button[starts-with(@id, 'submit')] is correct XPath syntax. Options B and C use invalid XPath operators.

3. Final Answer:

   //button[starts-with(@id, 'submit')] -> Option D

4. Quick Check:

   Starts with = starts-with() [OK]

Hint: Use starts-with(@attr, 'text') for prefix matching [OK]

Common Mistakes:

• Using contains() instead of starts-with() for prefix
• Using CSS selector syntax like ^= in XPath
• Incorrect function syntax or missing parentheses

3. Given the following HTML snippet:

<input type="text" id="user_email" value="[e-mail]"/>

What is the result of this XPath query?
//*[@id[contains(., 'user')]]

medium

A. Syntax error due to incorrect XPath function usage

B. Selects all elements with any id attribute

C. Selects the input element because its id contains 'user'

D. Selects no elements because 'user' is not in the value attribute

Solution

1. Step 1: Analyze the XPath syntax

   The XPath //*[@id[contains(., 'user')]] is syntactically incorrect because @id is an attribute node and cannot be used as a function or have predicates applied directly like this.

2. Step 2: Correct XPath syntax

   To check if the id attribute contains 'user', the correct XPath is //*[@id[contains(., 'user')]] is invalid; instead use //*[contains(@id, 'user')].

3. Final Answer:

   Syntax error due to incorrect XPath function usage -> Option A

4. Quick Check:

   Attribute predicates must be correctly formed [OK]

Hint: Use contains(@id, 'user') not @id[contains()] [OK]

Common Mistakes:

• Using predicates directly on attribute nodes
• Assuming . refers to attribute value in this context
• Incorrect predicate syntax

4. You wrote this XPath to find links starting with "http":
//a[contains(starts-with(@href, 'http'))]
Why does this XPath fail to find any elements?

medium

A. Because @href attribute is missing

B. Because contains() cannot wrap starts-with() function

C. Because starts-with() requires two arguments

D. Because the syntax is correct but no links start with 'http'

Solution

1. Step 1: Understand function nesting rules in XPath

   The contains() function expects two string arguments, but here it wraps starts-with() which returns a boolean, causing a syntax error.

2. Step 2: Correct usage

   Use either starts-with(@href, 'http') alone or contains(@href, 'http'), but not nested.

3. Final Answer:

   Because contains() cannot wrap starts-with() function -> Option B

4. Quick Check:

   Do not nest contains() and starts-with() [OK]

Hint: Do not nest XPath functions like contains(starts-with()) [OK]

Common Mistakes:

• Nesting contains() and starts-with() incorrectly
• Assuming starts-with() returns string for contains()
• Ignoring function argument requirements

5. You want to locate all <div> elements whose class attribute starts with "alert" but excludes those that contain "dismiss" anywhere in the class. Which XPath expression correctly achieves this?

hard

A. //div[starts-with(@class, 'alert') and not(contains(@class, 'dismiss'))]

B. //div[contains(@class, 'alert') and not(starts-with(@class, 'dismiss'))]

C. //div[starts-with(@class, 'alert') or not(contains(@class, 'dismiss'))]

D. //div[contains(@class, 'alert') or contains(@class, 'dismiss')]

Solution

1. Step 1: Use starts-with() to match class beginning

   The expression starts-with(@class, 'alert') selects elements whose class attribute begins with "alert".

2. Step 2: Exclude elements containing 'dismiss'

   The not(contains(@class, 'dismiss')) excludes elements whose class contains "dismiss" anywhere.

3. Step 3: Combine conditions with and

   Both conditions must be true, so use and to combine them.

4. Final Answer:

   //div[starts-with(@class, 'alert') and not(contains(@class, 'dismiss'))] -> Option A

5. Quick Check:

   Starts with alert AND no dismiss = //div[starts-with(@class, 'alert') and not(contains(@class, 'dismiss'))] [OK]

Hint: Combine starts-with() and not(contains()) with and [OK]

Common Mistakes:

• Using or instead of and causing wrong matches
• Mixing contains() and starts-with() incorrectly
• Forgetting to negate contains() for exclusion