Random Element is no longer attached to the DOM StaleElementReferenceException

Question

I m hoping it s just me  but Selenium Webdriver seems like a complete nightmare   The Chrome webdriver is currently unusable  and the other drivers are quite unreliable  or so it seems   I am battling many problems  but here is one     Randomly  my tests will fail with a    org openqa selenium StaleElementReferenceException  Element is no longer attached  to the DOM     System info  os name   Windows 7   os arch   amd64    os version   6 1   java version   1 6 0 23     I m using webdriver versions 2 0b3   I have seen this happen with FF and IE drivers   The only way I can prevent this is to add an actual call to Thread sleep before the exception occurs   That is a poor workaround though  so I m hoping someone can point out an error on my part that will make this all better

User · Answer

You can solve this by using explicit wait so that you don't have to use hard wait.

If you fetching all the elements with one property and iterating through it using for each loop you can use wait inside the loop like this,

List<WebElement> elements = driver.findElements("Object property");
for(WebElement element:elements)
{
    new WebDriverWait(driver,10).until(ExpectedConditions.presenceOfAllElementsLocatedBy("Object property"));
    element.click();//or any other action
}

or for single element you can use below code,

new WebDriverWait(driver,10).until(ExpectedConditions.presenceOfAllElementsLocatedBy("Your object property"));
driver.findElement("Your object property").click();//or anyother action

User · Answer

I get this error sometimes when AJAX updates are midway   Capybara appears to be pretty smart about waiting for DOM changes  see Why wait until was removed from Capybara    but the default wait time of 2 seconds was simply not enough in my case   Changed in  spec helper rb  with e g   Capybara default max wait time   5

User · Answer

I have been able to use a method like this with some success   WebElement getStaleElemById String id        try           return driver findElement By id id          catch  StaleElementReferenceException e            System out println  Attempting to recover from StaleElementReferenceException                return getStaleElemById id             Yes  it just keeps polling the element until it s no longer considered stale  fresh    Doesn t really get to the root of the problem  but I ve found that the WebDriver can be rather picky about throwing this exception -- sometimes I get it  and sometimes I don t  Or it could be that the DOM really is changing   So I don t quite agree with the answer above that this necessarily indicates a poorly-written test  I ve got it on fresh pages which I have not interacted with in any way  I think there is some flakiness in either how the DOM is represented  or in what WebDriver considers to be stale

User · Answer

In Java 8 you can use very simple method for that   private Object retryUntilAttached Supplier lt Object gt  callable        try           return callable get          catch  StaleElementReferenceException e            log warn   tTrying once again            return retryUntilAttached callable

User · Answer

To add to  jarib s answer  I have made several extension methods which help eliminate the race condition   Here is my setup   I have a class Called  Driver cs   It contains a static class full of extension methods for the driver and other useful static functions   For elements I commonly need to retrieve  I create an extension method like the following   public static IWebElement SpecificElementToGet this IWebDriver driver        return driver FindElement By SomeSelector  SelectorText         This allows you to retrieve that element from any test class with the code   driver SpecificElementToGet      Now  if this results in a StaleElementReferenceException  I have the following static method in my driver class   public static void WaitForDisplayed Func lt IWebElement gt  getWebElement  int timeOut        for  int second   0    second                  if  second  gt   timeOut  Assert Fail  timeout            try                       if  getWebElement   Displayed  break                    catch  Exception                      Thread Sleep 1000             This function s first parameter is any function which returns an IWebElement object  The second parameter is a timeout in seconds  the code for the timeout was copied from the Selenium IDE for FireFox   The code can be used to avoid the stale element exception the following way   MyTestDriver WaitForDisplayed driver SpecificElementToGet 5     The above code will call driver SpecificElementToGet   Displayed until driver SpecificElementToGet   throws no exceptions and  Displayed evaluates to true and 5 seconds have not passed  After 5 seconds  the test will fail   On the flip side  to wait for an element to not be present  you can use the following function the same way   public static void WaitForNotPresent Func lt IWebElement gt  getWebElement  int timeOut        for  int second   0   second              if  second  gt   timeOut  Assert Fail  timeout                try                               if   getWebElement   Displayed  break                            catch  ElementNotVisibleException    break                catch  NoSuchElementException    break                catch  StaleElementReferenceException    break                catch  Exception                              Thread Sleep 1000

User · Answer

I was facing the same problem today and made up a wrapper class  which checks before every method if the element reference is still valid  My solution to retrive the element is pretty simple so i thought i d just share it   private void setElementLocator         this locatorVariable    selenium     DateTimeMethods GetTime   ToString          IJavaScriptExecutor this driver  ExecuteScript locatorVariable       arguments 0     this element      private void RetrieveElement         this element    IWebElement   IJavaScriptExecutor this driver  ExecuteScript  return     locatorVariable       You see i  locate  or rather save the element in a global js variable and retrieve the element if needed  If the page gets reloaded this reference will not work anymore  But as long as only changes are made to doom the reference stays  And that should do the job in most cases   Also it avoids re-searching the element   John

User · Answer

I think I found convenient approach to handle StaleElementReferenceException  Usually you have to write wrappers for every WebElement method to retry actions  which is frustrating and wastes lots of time   Adding this code  webDriverWait until  webDriver1  - gt     JavascriptExecutor  webDriver  executeScript  return document readyState   equals  complete       if   Boolean    JavascriptExecutor  webDriver  executeScript  return window jQuery    undefined          webDriverWait until  webDriver1  - gt     JavascriptExecutor  webDriver  executeScript  return jQuery active    0          before every WebElement action can increase stability of your tests but you still can get StaleElementReferenceException from time to time   So this is what I came up with  using AspectJ    package path to your aspects   import org apache logging log4j LogManager  import org apache logging log4j Logger  import org aspectj lang ProceedingJoinPoint  import org aspectj lang annotation Around  import org aspectj lang annotation Aspect  import org aspectj lang annotation Pointcut  import org aspectj lang reflect MethodSignature  import org openqa selenium JavascriptExecutor  import org openqa selenium StaleElementReferenceException  import org openqa selenium WebDriver  import org openqa selenium WebElement  import org openqa selenium remote RemoteWebElement  import org openqa selenium support pagefactory DefaultElementLocator  import org openqa selenium support pagefactory internal LocatingElementHandler  import org openqa selenium support ui WebDriverWait   import java lang reflect Field  import java lang reflect Method  import java lang reflect Proxy    Aspect public class WebElementAspect       private static final Logger LOG   LogManager getLogger WebElementAspect class                  Get your WebDriver instance from some kind of manager             private WebDriver webDriver   DriverManager getWebDriver        private WebDriverWait webDriverWait   new WebDriverWait webDriver  10                   This will intercept execution of all methods from WebElement interface              Pointcut  execution   org openqa selenium WebElement              public void webElementMethods                       Around annotation means that you can insert additional logic        before and after execution of the method              Around  webElementMethods         public Object webElementHandler ProceedingJoinPoint joinPoint  throws Throwable                          Waiting until JavaScript and jQuery complete their stuff                     waitUntilPageIsLoaded                            Getting WebElement instance  method  arguments                     WebElement webElement    WebElement  joinPoint getThis            Method method     MethodSignature  joinPoint getSignature    getMethod            Object   args   joinPoint getArgs                            Do some logging if you feel like it                     String methodName   method getName             if  methodName contains  click                  LOG info  Clicking on     getBy webElement              else if  methodName contains  select                  LOG info  Selecting from     getBy webElement              else if  methodName contains  sendKeys                  LOG info  Entering     args 0  toString       into     getBy webElement                       try                                  Executing WebElement method                             return joinPoint proceed              catch  StaleElementReferenceException ex                LOG debug  Intercepted StaleElementReferenceException                                    Refreshing WebElement                You can use implementation from this blog                http   www sahajamit com post mystery-of-stale-element-reference-exception                 but remove staleness check in the beginning  if  isElementStale elem     because we already caught exception                and it will result in an endless loop                             webElement   StaleElementUtil refreshElement webElement                                   Executing method once again on the refreshed WebElement and returning result                             return method invoke webElement  args                        private void waitUntilPageIsLoaded             webDriverWait until  webDriver1  - gt     JavascriptExecutor  webDriver  executeScript  return document readyState   equals  complete               if   Boolean    JavascriptExecutor  webDriver  executeScript  return window jQuery    undefined                  webDriverWait until  webDriver1  - gt     JavascriptExecutor  webDriver  executeScript  return jQuery active    0                           private static String getBy WebElement webElement            try               if  webElement instanceof RemoteWebElement                    try                       Field foundBy   webElement getClass   getDeclaredField  foundBy                        foundBy setAccessible true                       return  String  foundBy get webElement                     catch  NoSuchFieldException e                        e printStackTrace                                    else                   LocatingElementHandler handler    LocatingElementHandler  Proxy getInvocationHandler webElement                    Field locatorField   handler getClass   getDeclaredField  locator                    locatorField setAccessible true                    DefaultElementLocator locator    DefaultElementLocator  locatorField get handler                    Field byField   locator getClass   getDeclaredField  by                    byField setAccessible true                    return byField get locator  toString                            catch  IllegalAccessException   NoSuchFieldException e                e printStackTrace                       return null            To enable this aspect create file  src main resources META-INF aop-ajc xml  and write   lt aspectj gt       lt aspects gt           lt aspect name  path to your aspects WebElementAspect   gt       lt  aspects gt   lt  aspectj gt    Add this to your pom xml   lt properties gt       lt aspectj version gt 1 9 1 lt  aspectj version gt   lt  properties gt    lt build gt       lt plugins gt           lt plugin gt               lt groupId gt org apache maven plugins lt  groupId gt               lt artifactId gt maven-surefire-plugin lt  artifactId gt               lt version gt 2 22 0 lt  version gt               lt configuration gt                   lt argLine gt                      -javaagent    settings localRepository  org aspectj aspectjweaver   aspectj version  aspectjweaver-  aspectj version  jar                   lt  argLine gt               lt  configuration gt               lt dependencies gt                   lt dependency gt                       lt groupId gt org aspectj lt  groupId gt                       lt artifactId gt aspectjweaver lt  artifactId gt                       lt version gt   aspectj version  lt  version gt                   lt  dependency gt               lt  dependencies gt           lt  plugin gt   lt  build gt    And thats all  Hope it helps

User · Answer

Yes  if you re having problems with StaleElementReferenceExceptions it s because there is a race condition  Consider the following scenario  WebElement element   driver findElement By id  quot foo quot        DOM changes - page is refreshed  or element is removed and re-added element click     Now at the point where you re clicking the element  the element reference is no longer valid  It s close to impossible for WebDriver to make a good guess about all the cases where this might happen - so it throws up its hands and gives control to you  who as the test app author should know exactly what may or may not happen  What you want to do is explicitly wait until the DOM is in a state where you know things won t change  For example  using a WebDriverWait to wait for a specific element to exist     times out after 5 seconds WebDriverWait wait   new WebDriverWait driver  5           while the following loop runs  the DOM changes -     page is refreshed  or element is removed and re-added wait until presenceOfElementLocated By id  quot container-element quot                  now we re good - let s click the element driver findElement By id  quot foo quot    click     The presenceOfElementLocated   method would look something like this  private static Function lt WebDriver WebElement gt  presenceOfElementLocated final By locator        return new Function lt WebDriver  WebElement gt               Override         public WebElement apply WebDriver driver                return driver findElement locator                       You re quite right about the current Chrome driver being quite unstable  and you ll be happy to hear that the Selenium trunk has a rewritten Chrome driver  where most of the implementation was done by the Chromium developers as part of their tree  PS  Alternatively  instead of waiting explicitly like in the example above  you can enable implicit waits - this way WebDriver will always loop up until the specified timeout waiting for the element to become present  driver manage   timeouts   implicitlyWait 10  TimeUnit SECONDS   In my experience though  explicitly waiting is always more reliable

User · Answer

FirefoxDriver  driver   new FirefoxDriver        create webdriverwait WebDriverWait wait   new WebDriverWait  driver  TimeSpan FromSeconds 10        create flag checker bool result   false      wait for the element  IWebElement elem   wait Until x   gt  x FindElement By Id  Element ID       do       try                  let the driver look for the element again          elem    driver FindElement By Id  Element ID                 do your actions          elem SendKeys  text                it will throw an exception if the element is not in the dom or not            found but if it didn t  our result will be changed to true          result    result            catch  Exception        while  result    true      this will continue to look for the element until                              it ends throwing exception

User · Answer

Just happened to me when trying to send keys to a search input box - that has autoupdate depending on what you type in  As mentioned by Eero  this can happen if your element does some Ajax updated while you are typing in your text inside the input element  The solution is to send one character at a time and search again for the input element   Ex  in ruby shown below   def send keys eachchar webdriver  elem locator  text to send    text to send each char do  char      input elem   webdriver find element elem locator      input elem send keys char    end end

User · Answer

I had the same problem and mine was caused by an old selenium version  I cannot update to a newer version due to development environment  The problem is caused by HTMLUnitWebElement switchFocusToThisIfNeeded    When you navigate to a new page it might happen that the element you clicked on the old page is the oldActiveElement  see below   Selenium tries to get context from the old element and fails  That s why they built a try catch in future releases   Code from selenium-htmlunit-driver version  lt  2 23 0   private void switchFocusToThisIfNeeded         HtmlUnitWebElement oldActiveElement             HtmlUnitWebElement parent switchTo   activeElement          boolean jsEnabled   parent isJavascriptEnabled        boolean oldActiveEqualsCurrent   oldActiveElement equals this       boolean isBody   oldActiveElement getTagName   toLowerCase   equals  body        if  jsEnabled  amp  amp           oldActiveEqualsCurrent  amp  amp           isBody          oldActiveElement element blur          element focus              Code from selenium-htmlunit-driver version    2 23 0   private void switchFocusToThisIfNeeded         HtmlUnitWebElement oldActiveElement             HtmlUnitWebElement parent switchTo   activeElement          boolean jsEnabled   parent isJavascriptEnabled        boolean oldActiveEqualsCurrent   oldActiveElement equals this       try           boolean isBody   oldActiveElement getTagName   toLowerCase   equals  body            if  jsEnabled  amp  amp               oldActiveEqualsCurrent  amp  amp               isBody            oldActiveElement element blur                    catch  StaleElementReferenceException ex             old element has gone  do nothing           element focus        Without updating to 2 23 0 or newer you can just give any element on the page focus  I just used element click   for example

[java] Random "Element is no longer attached to the DOM" StaleElementReferenceException

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