查询网络元素

根据提供的定位值定位元素.

One of the most fundamental aspects of using Selenium is obtaining element references to work with. Selenium offers a number of built-in locator strategies to uniquely identify an element. There are many ways to use the locators in very advanced scenarios. For the purposes of this documentation, let’s consider this HTML snippet:

<ol id="vegetables">
 <li class="potatoes"> <li class="onions"> <li class="tomatoes"><span>Tomato is a Vegetable</span></ol>
<ul id="fruits">
  <li class="bananas">  <li class="apples">  <li class="tomatoes"><span>Tomato is a Fruit</span></ul>

First matching element

Many locators will match multiple elements on the page. The singular find element method will return a reference to the first element found within a given context.

Evaluating entire DOM

When the find element method is called on the driver instance, it returns a reference to the first element in the DOM that matches with the provided locator. This value can be stored and used for future element actions. In our example HTML above, there are two elements that have a class name of “tomatoes” so this method will return the element in the “vegetables” list.

WebElement vegetable = driver.findElement(By.className("tomatoes"));
  
vegetable = driver.find_element(By.CLASS_NAME, "tomatoes")
  
var vegetable = driver.FindElement(By.ClassName("tomatoes"));
  
vegetable = driver.find_element(class: 'tomatoes')
  
const vegetable = driver.findElement(By.className('tomatoes'));
  
val vegetable: WebElement = driver.findElement(By.className("tomatoes"))
  

Evaluating a subset of the DOM

Rather than finding a unique locator in the entire DOM, it is often useful to narrow the search to the scope of another located element. In the above example there are two elements with a class name of “tomatoes” and it is a little more challenging to get the reference for the second one.

One solution is to locate an element with a unique attribute that is an ancestor of the desired element and not an ancestor of the undesired element, then call find element on that object:

WebElement fruits = driver.findElement(By.id("fruits"));
WebElement fruit = fruits.findElement(By.id("tomatoes"));
  
fruits = driver.find_element(By.ID, "fruits")
fruit = fruits.find_elements_by_id("tomatoes")
  
IWebElement fruits = driver.FindElement(By.Id("fruits"));
IWebElement fruit = fruits.FindElement(By.Id("tomatoes"));
  
fruits = driver.find_element(id: 'fruits')
fruit = fruits.find_element(id: 'tomatoes')
  
const fruits = driver.findElement(By.id('fruits'));
const fruit = fruits.findElement(By.id('tomatoes'));
  
val fruits = driver.findElement(By.id("fruits"))
val fruit = fruits.findElement(By.id("tomatoes"))
  

Java and C#
WebDriver, WebElement and ShadowRoot classes all implement a SearchContext interface, which is considered a role-based interface. Role-based interfaces allow you to determine whether a particular driver implementation supports a given feature. These interfaces are clearly defined and try to adhere to having only a single role of responsibility.

Optimized locator

A nested lookup might not be the most effective location strategy since it requires two separate commands to be issued to the browser.

To improve the performance slightly, we can use either CSS or XPath to find this element in a single command. See the Locator strategy suggestions in our Encouraged test practices section.

For this example, we’ll use a CSS Selector:

WebElement fruit = driver.findElement(By.cssSelector("#fruits .tomatoes"));
  
fruit = driver.find_element_by_css_selector("#fruits .tomatoes")
  
var fruit = driver.FindElement(By.CssSelector("#fruits .tomatoes"));
  
fruit = driver.find_element(css: '#fruits .tomatoes')
  
const fruit = driver.findElement(By.css('#fruits .tomatoes'));
  
val fruit = driver.findElement(By.cssSelector("#fruits .tomatoes"))
  

All matching elements

There are several use cases for needing to get references to all elements that match a locator, rather than just the first one. The plural find elements methods return a collection of element references. If there are no matches, an empty list is returned. In this case, references to all fruits and vegetable list items will be returned in a collection.

List<WebElement> plants = driver.findElements(By.tagName("li"));
  
plants = driver.find_elements(By.TAG_NAME, "li")
  
IReadOnlyList<IWebElement> plants = driver.FindElements(By.TagName("li"));
  
plants = driver.find_elements(tag_name: 'li')
  
const plants = driver.findElements(By.tagName('li'));
  
val plants: List<WebElement> = driver.findElements(By.tagName("li"))
  

Get element

Often you get a collection of elements but want to work with a specific element, which means you need to iterate over the collection and identify the one you want.

List<WebElement> elements = driver.findElements(By.tagName("li"));

for (WebElement element : elements) {
    System.out.println("Paragraph text:" + element.getText());
}
  
from selenium import webdriver
from selenium.webdriver.common.by import By

driver = webdriver.Firefox()

    # Navigate to Url
driver.get("https://www.example.com")

    # Get all the elements available with tag name 'p'
elements = driver.find_elements(By.TAG_NAME, 'p')

for e in elements:
    print(e.text)
  
using OpenQA.Selenium;
using OpenQA.Selenium.Firefox;
using System.Collections.Generic;

namespace FindElementsExample {
 class FindElementsExample {
  public static void Main(string[] args) {
   IWebDriver driver = new FirefoxDriver();
   try {
    // Navigate to Url
    driver.Navigate().GoToUrl("https://example.com");

    // Get all the elements available with tag name 'p'
    IList < IWebElement > elements = driver.FindElements(By.TagName("p"));
    foreach(IWebElement e in elements) {
     System.Console.WriteLine(e.Text);
    }

   } finally {
    driver.Quit();
   }
  }
 }
}
  
require 'selenium-webdriver'
driver = Selenium::WebDriver.for :firefox
begin
     # Navigate to URL
  driver.get 'https://www.example.com'

     # Get all the elements available with tag name 'p'
  elements = driver.find_elements(:tag_name,'p')

  elements.each { |e|
    puts e.text
  }
ensure
  driver.quit
end
  
const {Builder, By} = require('selenium-webdriver');
(async function example() {
    let driver = await new Builder().forBrowser('firefox').build();
    try {
        // Navigate to Url
        await driver.get('https://www.example.com');

        // Get all the elements available with tag 'p'
        let elements = await driver.findElements(By.css('p'));
        for(let e of elements) {
            console.log(await e.getText());
        }
    }
    finally {
        await driver.quit();
    }
})();
  
import org.openqa.selenium.By
import org.openqa.selenium.firefox.FirefoxDriver

fun main() {
    val driver = FirefoxDriver()
    try {
        driver.get("https://example.com")
        // Get all the elements available with tag name 'p'
        val elements = driver.findElements(By.tagName("p"))
        for (element in elements) {
            println("Paragraph text:" + element.text)
        }
    } finally {
        driver.quit()
    }
}
  

Find Elements From Element

It is used to find the list of matching child WebElements within the context of parent element. To achieve this, the parent WebElement is chained with ‘findElements’ to access child elements

  import org.openqa.selenium.By;
  import org.openqa.selenium.WebDriver;
  import org.openqa.selenium.WebElement;
  import org.openqa.selenium.chrome.ChromeDriver;
  import java.util.List;

  public class findElementsFromElement {
      public static void main(String[] args) {
          WebDriver driver = new ChromeDriver();
          try {
              driver.get("https://example.com");

              // Get element with tag name 'div'
              WebElement element = driver.findElement(By.tagName("div"));

              // Get all the elements available with tag name 'p'
              List<WebElement> elements = element.findElements(By.tagName("p"));
              for (WebElement e : elements) {
                  System.out.println(e.getText());
              }
          } finally {
              driver.quit();
          }
      }
  }
  
from selenium import webdriver
from selenium.webdriver.common.by import By

driver = webdriver.Chrome()
driver.get("https://www.example.com")

    # Get element with tag name 'div'
element = driver.find_element(By.TAG_NAME, 'div')

    # Get all the elements available with tag name 'p'
elements = element.find_elements(By.TAG_NAME, 'p')
for e in elements:
    print(e.text)
  
using OpenQA.Selenium;
using OpenQA.Selenium.Chrome;
using System.Collections.Generic;

namespace FindElementsFromElement {
 class FindElementsFromElement {
  public static void Main(string[] args) {
   IWebDriver driver = new ChromeDriver();
   try {
    driver.Navigate().GoToUrl("https://example.com");

    // Get element with tag name 'div'
    IWebElement element = driver.FindElement(By.TagName("div"));

    // Get all the elements available with tag name 'p'
    IList < IWebElement > elements = element.FindElements(By.TagName("p"));
    foreach(IWebElement e in elements) {
     System.Console.WriteLine(e.Text);
    }
   } finally {
    driver.Quit();
   }
  }
 }
}
  
  require 'selenium-webdriver'
  driver = Selenium::WebDriver.for :chrome
  begin
    # Navigate to URL
    driver.get 'https://www.example.com'

    # Get element with tag name 'div'
    element = driver.find_element(:tag_name,'div')

    # Get all the elements available with tag name 'p'
    elements = element.find_elements(:tag_name,'p')

    elements.each { |e|
      puts e.text
    }
  ensure
    driver.quit
  end
  
  const {Builder, By} = require('selenium-webdriver');

  (async function example() {
      let driver = new Builder()
          .forBrowser('chrome')
          .build();

      await driver.get('https://www.example.com');

      // Get element with tag name 'div'
      let element = driver.findElement(By.css("div"));

      // Get all the elements available with tag name 'p'
      let elements = await element.findElements(By.css("p"));
      for(let e of elements) {
          console.log(await e.getText());
      }
  })();
  
  import org.openqa.selenium.By
  import org.openqa.selenium.chrome.ChromeDriver

  fun main() {
      val driver = ChromeDriver()
      try {
          driver.get("https://example.com")

          // Get element with tag name 'div'
          val element = driver.findElement(By.tagName("div"))

          // Get all the elements available with tag name 'p'
          val elements = element.findElements(By.tagName("p"))
          for (e in elements) {
              println(e.text)
          }
      } finally {
          driver.quit()
      }
  }
  

Get Active Element

It is used to track (or) find DOM element which has the focus in the current browsing context.

  import org.openqa.selenium.*;
  import org.openqa.selenium.chrome.ChromeDriver;

  public class activeElementTest {
    public static void main(String[] args) {
      WebDriver driver = new ChromeDriver();
      try {
        driver.get("http://www.google.com");
        driver.findElement(By.cssSelector("[name='q']")).sendKeys("webElement");

        // Get attribute of current active element
        String attr = driver.switchTo().activeElement().getAttribute("title");
        System.out.println(attr);
      } finally {
        driver.quit();
      }
    }
  }
  
  from selenium import webdriver
  from selenium.webdriver.common.by import By

  driver = webdriver.Chrome()
  driver.get("https://www.google.com")
  driver.find_element(By.CSS_SELECTOR, '[name="q"]').send_keys("webElement")

    # Get attribute of current active element
  attr = driver.switch_to.active_element.get_attribute("title")
  print(attr)
  
    using OpenQA.Selenium;
    using OpenQA.Selenium.Chrome;

    namespace ActiveElement {
     class ActiveElement {
      public static void Main(string[] args) {
       IWebDriver driver = new ChromeDriver();
       try {
        // Navigate to Url
        driver.Navigate().GoToUrl("https://www.google.com");
        driver.FindElement(By.CssSelector("[name='q']")).SendKeys("webElement");

        // Get attribute of current active element
        string attr = driver.SwitchTo().ActiveElement().GetAttribute("title");
        System.Console.WriteLine(attr);
       } finally {
        driver.Quit();
       }
      }
     }
    }
  
  require 'selenium-webdriver'
  driver = Selenium::WebDriver.for :chrome
  begin
    driver.get 'https://www.google.com'
    driver.find_element(css: '[name="q"]').send_keys('webElement')

    # Get attribute of current active element
    attr = driver.switch_to.active_element.attribute('title')
    puts attr
  ensure
    driver.quit
  end
  
  const {Builder, By} = require('selenium-webdriver');

  (async function example() {
      let driver = await new Builder().forBrowser('chrome').build();
      await driver.get('https://www.google.com');
      await  driver.findElement(By.css('[name="q"]')).sendKeys("webElement");

      // Get attribute of current active element
      let attr = await driver.switchTo().activeElement().getAttribute("title");
      console.log(`${attr}`)
  })();
  
  import org.openqa.selenium.By
  import org.openqa.selenium.chrome.ChromeDriver

  fun main() {
      val driver = ChromeDriver()
      try {
          driver.get("https://www.google.com")
          driver.findElement(By.cssSelector("[name='q']")).sendKeys("webElement")

          // Get attribute of current active element
          val attr = driver.switchTo().activeElement().getAttribute("title")
          print(attr)
      } finally {
          driver.quit()
      }
  }