Play with scroll bars on a page in selenium and javaScript

There are some situations in which we want to scroll to a particular element or scroll up or down across the browser.

Selenium do not have it's own methods to perform this action, so we can use javascript to play on scroll lbars.

Let's see some of the ways:

public class Test1 {

 public static void main(String[] args) {
  WebDriver driver;
  driver = new FirefoxDriver();
  driver.get("http://www.qavalidation.com/p/demo.html");
  
  JavascriptExecutor js = (JavascriptExecutor) driver;
  //Scroll page down to 250px
  js.executeScript("window.scrollBy(0,250)", "");
  //or
  //js.executeScript("scroll(0,250)");
  
  //Scroll page to view an element 
  WebElement element = null;
  element = (WebElement) js.executeScript("return document.getElementById('table01');");
  js.executeScript("arguments[0].scrollIntoView(true);",element);
 }
}