Locating elements using id, name, or class attributes is the preferred way to find elements. Let's try using these methods to locate elements as described in the following sections.

Finding elements by the ID attribute

Using the id attribute is the most preferable way to locate elements on a page. The W3C standard recommends that developers provide an id attribute for elements that are unique to each element. Having a unique id attribute provides a very explicit and reliable way to locate elements on the page.

While processing the DOM, browsers use id as the preferred way to identify the elements and this provides the fastest locator strategy.

Let's now look at how to use id attributes for locating elements on a login form.

<form name="loginForm">
    <label for="username">UserName: </label> <input type="text" id="username" /><br/>
    <label for="password">Password: </label> <input type="password" id="password" /><br/>
    <input name="login" type="submit" value="Login" />
</form>

To locate the User Name and Password fields, we can use the id attribute in the following way:

WebElement username = driver.findElement(By.id("username"));
WebElement password = driver.findElement(By.id("password"));

Finding elements by the Name attribute

Locating elements with the id attribute is the most preferred locator strategy, but you might find situations where you cannot use the id attribute due to the following reasons:

In this example, the login form elements use the name attribute instead of the id attribute:

<form name="loginForm">
    <label for="username">UserName: </label> <input type="text" name="username" /><br/>
    <label for="password">Password: </label> <input type="password" name="password" /><br/>
    <input name="login" type="submit" value="Login" />
</form>

We can use the name attribute to locate elements in the following way:

WebElement username = driver.findElement(By.name("username"));
WebElement password = driver.findElement(By.name("password"));

Unlike id, the name attribute may not be unique on a page. You might find multiple elements with similar name attributes and in such a case, the first element on the page with the specified value will be selected, which may not be the element you are looking for. This may cause the test to fail.

Finding elements by the Class attribute

Apart from using the id and name attributes, you can also use the class attribute to locate elements. The class attribute is provided to apply CSS to an element.

In this example, the login form elements use the class attribute instead of the id attribute:

<form name="loginForm">
    <label for="username">UserName: </label> <input type="text" class="username" /></br>
    <label for="password">Password: </label> <input type="password" class="password" /></br>
    <input name="login" type="submit" value="Login" />
</form>

We can use the class attribute to locate elements in the following way:

WebElement username = driver.findElement(By.className("username"));
WebElement password = driver.findElement(By.className("password"));

Selenium WebDriver API provides the findElement() method to locate the elements that are required in a test from the page under test.

When locating an element matching specified criteria, it looks through the DOM (Document Object Model) for matching elements and returns the first matching element to the test.

The WebElement class also supports find methods that find child elements. For example, imagine that there are some duplicate elements on a page. However, they are located in separate <div> elements. We can first locate the parent <div> element and then locate the child element within the context of the <div> element in the following way:

WebElement div = driver.findElement(By.id("div1"));
WebElement topLink = div.findElement(By.linkText("top"));

You can also a use a shortcut method in the following way:

WebElement topLink = driver.findElement(By.id("div1")).findElement(By.linkText("top"));

NoSuchElementFoundException

The findElement() and FindElements() methods throw up the NoSuchElementFoundException exception when they fail to find the desired element using the specified locator strategy.