Web Driver click on element within ShadowDOM is returning error "{"message":"unknown error: Cannot read property 'defaultView' of undefined"

Question

I have a website built with Polymer 2 with a DOM structure that looks like:

...
<df-link slot="local-nav-drawer-link" link-href="/dictionary" text-color="light">
    #shadow-root (open)
    <a href="/dictionary" title="">
        <dom-if style="display: none;">
            <template is="dom-if"></template>
        </dom-if>
        <span class="dfpl-link__text">Dictionary</span>
    </a>
</df-link>
...

Using the page object pattern which defines the shadow root and the element I want to click as:

@FindBy(css = "df-link")
public WebElement shadowRootElement;

public By shadowAnchorElementSelector = By.cssSelector("a");

The code to retrieve the shadow root element looks like:

WebElement shadowRoot;
shadowRoot = (WebElement) jsExec.executeScript("return arguments[0].shadowRoot;", shadowRootElement);
WebElement anchor = shadowRoot.findElement(shadowAnchorElementSelector);
anchor.click();

I can successfully get attribute values, css values, and the inner text. However when I call a click this is what happens.

Apr 18, 2018 10:25:28 AM org.openqa.selenium.remote.server.WebDriverServlet handle
INFO: Found handler: org.openqa.selenium.remote.server.ServicedSession@136d9af5
Apr 18, 2018 10:25:28 AM org.openqa.selenium.remote.server.WebDriverServlet lambda$handle$0
INFO: Handler thread for session 2525b788dd3471e51e986fed682f04ea (chrome): 
Executing POST on /session/2525b788dd3471e51e986fed682f04ea/element/0.23700467091154298-6/click (handler: ServicedSession)
Apr 18, 2018 10:25:28 AM org.openqa.selenium.remote.server.Passthrough handle
INFO: To upstream: {"id":"0.23700467091154298-6"}
Apr 18, 2018 10:25:28 AM org.openqa.selenium.remote.server.Passthrough handle
INFO: To downstream: {"sessionId":"2525b788dd3471e51e986fed682f04ea","status":13,"value":{"message":"unknown error: Cannot read property 'defaultView' of undefined\n  (Session info: chrome=66.0.3359.117)\n  (Driver info: chromedriver=2.38.551601 (edb21f07fc70e9027c746edd3201443e011a61ed),platform=Windows NT 10.0.16299 x86_64)"}}

It looks as though the element is found fine, and I read from it, but as soon as I call WebElement.click() the error "Cannot read property 'defaultView' of undefined" is returned from ChromeDriver. I have not seen this posted around, and I am really stuck, wondering if someone has an answer for this.

This is with Chrome 66 and ChromeDriver 2.38.

Guessing here... Have you tried going down to the span and using click on it? Have you tried using 2.37 which also supports chrome 66. — Grasshopper, Apr 18 '18 at 18:26
@Grasshopper I have tried clicking the span with the same result. And I started with 2.37 with the same result as well.I have tried 2.37 with Chrome 65 and 66, and 2.38 with Chrome 66. — Nikolas Harris, Apr 18 '18 at 18:35

score 1 · Answer 1 · answered Feb 18 '19 at 19:34

1

I just had this issue and was able to fix it by using firefox and geckodriver instead of chrome driver. Fixed everything.

answered Feb 18 '19 at 19:34

Ethan King

19
2

Firefox also worked for me - but do we know why Chrome doesn't work correctly or how to resolve (without JavaScript click workarounds)? – jjurisch Jul 08 '19 at 17:02
Firefox did not support shadow DOM until version 63. – OliCoder Sep 20 '19 at 10:13

score 0 · Answer 2 · edited Oct 10 '19 at 10:03

0

Try with the below code

   public void forceClickElement(WebElement element){

        jsExec.executeScript("arguments[0].click();", element);
    }

edited Oct 10 '19 at 10:03

Ashok kumar Ganesan

1,098
5
20
48

answered Apr 25 '18 at 22:18

bbb

11

could you also explain what is the reason the code snipped from the question does not work and how this code fixes the issue? – saljuama Apr 25 '18 at 22:54
1

@bbb force clicking does work, but does not explain why the click does not. – Nikolas Harris Apr 27 '18 at 00:24

Web Driver click on element within ShadowDOM is returning error "{"message":"unknown error: Cannot read property 'defaultView' of undefined"

2 Answers2