HtmlUnit Exception

Question

I am having trouble understanding the meaning of this HTMLUnit Exception. It happens when I call click() on a link on a webpage.

Exception class=[net.sourceforge.htmlunit.corejs.javascript.WrappedException]
com.gargoylesoftware.htmlunit.ScriptException: Wrapped com.gargoylesoftware.htmlunit.ScriptException: TypeError: Cannot read property "offsetWidth" from null (http://webapps6.doc.state.nc.us/opi/scripts/DHTMLmessages.js#95) (javascript url#297)
at com.gargoylesoftware.htmlunit.javascript.JavaScriptEngine$HtmlUnitContextAction.run(JavaScriptEngine.java:534)
at net.sourceforge.htmlunit.corejs.javascript.Context.call(Context.java:537)
at net.sourceforge.htmlunit.corejs.javascript.ContextFactory.call(ContextFactory.java:538)
at com.gargoylesoftware.htmlunit.javascript.JavaScriptEngine.execute(JavaScriptEngine.java:432)
at com.gargoylesoftware.htmlunit.javascript.JavaScriptEngine.execute(JavaScriptEngine.java:407)
at com.gargoylesoftware.htmlunit.html.HtmlPage.executeJavaScriptIfPossible(HtmlPage.java:965)
at com.gargoylesoftware.htmlunit.html.HtmlAnchor.doClickAction(HtmlAnchor.java:87)
at com.gargoylesoftware.htmlunit.html.HtmlAnchor.doClickAction(HtmlAnchor.java:121)
at com.gargoylesoftware.htmlunit.html.HtmlElement.click(HtmlElement.java:1329)
at com.gargoylesoftware.htmlunit.html.HtmlElement.click(HtmlElement.java:1288)
at com.gargoylesoftware.htmlunit.html.HtmlElement.click(HtmlElement.java:1257)
at testapp.TestApp.main(TestApp.java:61)
Caused by: net.sourceforge.htmlunit.corejs.javascript.WrappedException: Wrapped com.gargoylesoftware.htmlunit.ScriptException: TypeError: Cannot read property "offsetWidth" from null (http://webapps6.doc.state.nc.us.js#95) (javascript url#297)
at net.sourceforge.htmlunit.corejs.javascript.Context.throwAsScriptRuntimeEx(Context.java:1802)
at net.sourceforge.htmlunit.corejs.javascript.MemberBox.invoke(MemberBox.java:196)
at net.sourceforge.htmlunit.corejs.javascript.FunctionObject.call(FunctionObject.java:479)
at net.sourceforge.htmlunit.corejs.javascript.Interpreter.interpretLoop(Interpreter.java:1701)
at net.sourceforge.htmlunit.corejs.javascript.Interpreter.interpret(Interpreter.java:854)
at net.sourceforge.htmlunit.corejs.javascript.InterpretedFunction.call(InterpretedFunction.java:164)
at net.sourceforge.htmlunit.corejs.javascript.ContextFactory.doTopCall(ContextFactory.java:429)
at com.gargoylesoftware.htmlunit.javascript.HtmlUnitContextFactory.doTopCall(HtmlUnitContextFactory.java:267)
at net.sourceforge.htmlunit.corejs.javascript.ScriptRuntime.doTopCall(ScriptRuntime.java:3183)
at net.sourceforge.htmlunit.corejs.javascript.InterpretedFunction.exec(InterpretedFunction.java:175)
at com.gargoylesoftware.htmlunit.javascript.JavaScriptEngine$5.doRun(JavaScriptEngine.java:423)
at com.gargoylesoftware.htmlunit.javascript.JavaScriptEngine$HtmlUnitContextAction.run(JavaScriptEngine.java:528)
... 11 more

From the stacktrace: Wrapped com.gargoylesoftware.htmlunit.ScriptException: TypeError: Cannot read property "offsetWidth" from null — Hoàng Long, Oct 08 '12 at 03:08
Add log4j as a dependency to stop HtmlUnit from printing those messages. — LanguagesNamedAfterCofee, Oct 08 '12 at 03:14

score 8 · Answer 1 · edited May 23 '17 at 10:31

When you click and this link call another page, htmlUnit can be very verbose on exceptions during navigation. If you click on your browser and open the console, probably will see those errors, missing links or images, errors on calling scripts..

Those are not necessary Javascript issues with HtmlUnit.

Like I said here HtmlUnit not creating HtmlPage object you can set or modify htmlUnit to prevent unecessary logs. You can also setup log4j and disable some exceptions.

So we use those options to keep html navegating without stoping on first error/problem we use :

webClient.getOptions().setThrowExceptionOnScriptError(false);
webClient.getOptions().setThrowExceptionOnFailingStatusCode(false);

You can also implement empty classes to stop htmlUnity go verbose on console about css/javaScript errors with:

webClient.setCssErrorHandler(new SilentCssErrorHandler());    
webClient.setJavaScriptErrorListener(new JavaScriptErrorListener(){});

The little sample test case:

@Test
public void TestCall() throws FailingHttpStatusCodeException, MalformedURLException, IOException {      
    WebClient webClient = new WebClient(BrowserVersion.CHROME);
    webClient.getOptions().setUseInsecureSSL(true); //ignore ssl certificate
    webClient.getOptions().setThrowExceptionOnScriptError(false);
    webClient.getOptions().setThrowExceptionOnFailingStatusCode(false);
    String url = "https://www.wearvr.com/#game_id=game_4";
    HtmlPage myPage = webClient.getPage(url);
    webClient.waitForBackgroundJavaScriptStartingBefore(200);
    webClient.waitForBackgroundJavaScript(20000);
    //do stuff on page ex: myPage.getElementById("main")
    //myPage.asXml() <- tags and elements
    System.out.println(myPage.asText());

}

Also you can see more here Turning HtmlUnit Warnings off

score 1 · Answer 2 · edited May 23 '17 at 12:18

1

JS issues with HtmlUnit again. You'll need to correct your JS code as it is very likely that it contains errors in it. If you don't own the JS code then HtmlUnit won't solve this issue. Take a look at the answer I've provided here.

edited May 23 '17 at 12:18

Community

1
1

answered Oct 08 '12 at 15:14

Mosty Mostacho

42,742
16
96
123

score 0 · Answer 3 · answered Oct 20 '16 at 07:48

0

Htmlunit generally does not handle js code pretty well. If you want to click on a link, it is better to find the element using the htmlunit api, eg.

    page.getHtmlElementById("some_div_id");
    page.getByXPath("//div");

answered Oct 20 '16 at 07:48

Kiriakos Diamantis

1

HtmlUnit Exception

3 Answers3

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