Limiting WebDriver scope is not working as expected-CodePudding

Can anyone please explain why data.size() is coming up as 13 and why data1.size() is coming up as 364?

As per my understanding, data.size() should be 0 because <td> is not a valid xpath expression and data1.size() should be 13 as there are 13 <td> tags inside/under the precipitation element. 364 is actually the total number of "td" tags in the particular webpage.

System.setProperty("webdriver.chrome.driver", "C:\\Program Files\\Java\\chromedriver.exe");
WebDriver driver = new ChromeDriver();
driver.manage().window().maximize();
driver.get("https://en.wikipedia.org/wiki/York");
Actions a = new Actions(driver);
WebElement precipitation = driver.findElement(By.xpath("//a[@title='Precipitation']//ancestor::tr"));
a.moveToElement(precipitation).build().perform();
List<WebElement> data = precipitation.findElements(By.xpath("td"));
List<WebElement> data1 = precipitation.findElements(By.xpath("//td"));
List<WebElement> data2 = precipitation.findElements(By.tagName("td"));
List<WebElement> data3 = precipitation.findElements(By.cssSelector("td"));
List<WebElement> data4 = driver.findElements(By.cssSelector("td"));
List<WebElement> data5 = driver.findElements(By.xpath("td"));
List<WebElement> data6 = driver.findElements(By.xpath("abcxyz"));
System.out.println("data = "  data.size());
System.out.println("data1 = "  data1.size());
System.out.println("data2 = "  data2.size());
System.out.println("data3 = "  data3.size());
System.out.println("data4 = "  data4.size());
System.out.println("data5 = "  data5.size());
System.out.println("data6 = "  data6.size());
driver.close();

CodePudding user response：

Actually "td" is a valid expression, it selects the nodes with node name td, and since you are not using / or // the search doesn't start in a higher element in the DOM hierarchy. This means that

precipitation.findElements(By.xpath("td"));

is the equivalent of

driver.findElement(By.xpath("//a[@title='Precipitation']//ancestor::tr/td"));

// will locate all the matching elements in the DOM, i.e. all the <td> nodes. If you want to use precipitation as the root node and start the search from there you need to add . for current context

precipitation.findElements(By.xpath(".//td"));

for all <td>s under the <tr>, or

precipitation.findElements(By.xpath("./td"));

for direct children of the <tr>

See XPath Syntax for reference.

CodePudding user response：

Selecting Nodes

XPath uses path expressions to select nodes in an XML document. The node is selected by the help of the following semantics:

Selecting Nodes

So as per the discussion above once you identify the webElement precipitation

WebElement precipitation = driver.findElement(By.xpath("//a[@title='Precipitation']//ancestor::tr"));

next to get the descendent <td> tags instead of:

List<WebElement> data = precipitation.findElements(By.xpath("td"));

As per the discussion above to identify the desired descendant <td> elements in the most effective way, you need to append the / character to denote from the from which node you would initiate the search.

So effectively, your line of code will be:

List<WebElement> data = precipitation.findElements(By.xpath(".//td"));

In a single line:

List<WebElement> data = precipitation.findElements(By.xpath("//a[@title='Precipitation']//ancestor::tr//td"));

which would select for you the correct 13 nos of desired <td> nodes.

td nodes