This fails if "#foobar" CSS selector fails to find the corresonpding ID.

Exception class=[net.sourceforge.htmlunit.corejs.javascript.JavaScriptException]
com.gargoylesoftware.htmlunit.ScriptException: TypeError: Cannot read property "parentNode" from null (http://localhost:38569/static/5bfaa01f/scripts/hudson-behavior.js#2430)
	at com.gargoylesoftware.htmlunit.javascript.JavaScriptEngine$HtmlUnitContextAction.run(JavaScriptEngine.java:528)
	at net.sourceforge.htmlunit.corejs.javascript.Context.call(Context.java:529)
	at net.sourceforge.htmlunit.corejs.javascript.ContextFactory.call(ContextFactory.java:536)
	at com.gargoylesoftware.htmlunit.javascript.JavaScriptEngine.execute(JavaScriptEngine.java:424)
	at com.gargoylesoftware.htmlunit.javascript.JavaScriptEngine.execute(JavaScriptEngine.java:399)
	at com.gargoylesoftware.htmlunit.html.HtmlPage.executeJavaScriptIfPossible(HtmlPage.java:892)
	at com.gargoylesoftware.htmlunit.html.HtmlScript.executeInlineScriptIfNeeded(HtmlScript.java:309)
	at com.gargoylesoftware.htmlunit.html.HtmlScript.executeScriptIfNeeded(HtmlScript.java:364)
	at com.gargoylesoftware.htmlunit.html.HtmlScript$1.execute(HtmlScript.java:223)
	at com.gargoylesoftware.htmlunit.html.HtmlScript.onAllChildrenAddedToPage(HtmlScript.java:238)
	at com.gargoylesoftware.htmlunit.html.HTMLParser$HtmlUnitDOMBuilder.endElement(HTMLParser.java:699)
	at org.apache.xerces.parsers.AbstractSAXParser.endElement(Unknown Source)
	at com.gargoylesoftware.htmlunit.html.HTMLParser$HtmlUnitDOMBuilder.endElement(HTMLParser.java:657)
	at org.cyberneko.html.HTMLTagBalancer.callEndElement(HTMLTagBalancer.java:1132)
	at org.cyberneko.html.HTMLTagBalancer.endElement(HTMLTagBalancer.java:1034)
	at org.cyberneko.html.filters.DefaultFilter.endElement(DefaultFilter.java:206)
	at org.cyberneko.html.filters.NamespaceBinder.endElement(NamespaceBinder.java:329)
	at org.cyberneko.html.HTMLScanner$ContentScanner.scanEndElement(HTMLScanner.java:3058)
	at org.cyberneko.html.HTMLScanner$ContentScanner.scan(HTMLScanner.java:1994)
	at org.cyberneko.html.HTMLScanner.scanDocument(HTMLScanner.java:907)
	at org.cyberneko.html.HTMLConfiguration.parse(HTMLConfiguration.java:499)
	at org.cyberneko.html.HTMLConfiguration.parse(HTMLConfiguration.java:452)
	at org.apache.xerces.parsers.XMLParser.parse(Unknown Source)
	at com.gargoylesoftware.htmlunit.html.HTMLParser$HtmlUnitDOMBuilder.parse(HTMLParser.java:901)
	at com.gargoylesoftware.htmlunit.html.HTMLParser.parse(HTMLParser.java:350)
	at com.gargoylesoftware.htmlunit.html.HTMLParser.parseHtml(HTMLParser.java:304)
	at com.gargoylesoftware.htmlunit.DefaultPageCreator.createHtmlPage(DefaultPageCreator.java:134)
	at com.gargoylesoftware.htmlunit.DefaultPageCreator.createPage(DefaultPageCreator.java:101)
	at org.jvnet.hudson.test.HudsonPageCreator.createPage(HudsonPageCreator.java:46)
	at com.gargoylesoftware.htmlunit.WebClient.loadWebResponseInto(WebClient.java:449)
	at com.gargoylesoftware.htmlunit.WebClient.getPage(WebClient.java:332)
	at com.gargoylesoftware.htmlunit.WebClient.getPage(WebClient.java:389)
	at com.gargoylesoftware.htmlunit.WebClient.getPage(WebClient.java:374)
	at org.jvnet.hudson.test.HudsonTestCase$WebClient.goTo(HudsonTestCase.java:1744)
	at org.jvnet.hudson.test.HudsonTestCase$WebClient.goTo(HudsonTestCase.java:1735)
	at hudson.model.JobPropertyTest.assertJobPropertySummaryIsShownInIndexPage(JobPropertyTest.java:59)
	at hudson.model.JobPropertyTest.testJobPropertySummaryIsShownInMatrixProjectIndexPage(JobPropertyTest.java:48)
	at org.jvnet.hudson.test.HudsonTestCase.runTest(HudsonTestCase.java:386)
	at org.jvnet.hudson.test.HudsonTestCase.runBare(HudsonTestCase.java:277)
	at com.sun.maven.junit.LocalTestCaseRunner.runTests(LocalTestCaseRunner.java:142)
	at com.sun.maven.junit.LocalTestCaseRunner.runTestCase(LocalTestCaseRunner.java:62)
	at com.sun.maven.junit.LocalTestCaseRunner.runTestCase(LocalTestCaseRunner.java:58)
	at hudson.remoting.RemoteInvocationHandler$RPCRequest.perform(RemoteInvocationHandler.java:274)
	at hudson.remoting.RemoteInvocationHandler$RPCRequest.call(RemoteInvocationHandler.java:255)
	at hudson.remoting.RemoteInvocationHandler$RPCRequest.call(RemoteInvocationHandler.java:215)
	at hudson.remoting.UserRequest.perform(UserRequest.java:118)
	at hudson.remoting.UserRequest.perform(UserRequest.java:48)
	at hudson.remoting.Request$2.run(Request.java:270)
	at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:441)
	at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
	at java.util.concurrent.FutureTask.run(FutureTask.java:138)
	at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
	at java.lang.Thread.run(Thread.java:662)
Caused by: net.sourceforge.htmlunit.corejs.javascript.JavaScriptException: TypeError: Cannot read property "parentNode" from null (http://localhost:38569/static/5bfaa01f/scripts/hudson-behavior.js#2430)
	at script.(http://localhost:38569/static/5bfaa01f/scripts/hudson-behavior.js:2430)
	at script.(http://localhost:38569/static/5bfaa01f/scripts/prototype.js:1126)
	at script.(http://localhost:38569/static/5bfaa01f/scripts/prototype.js:1072)
	at script.(http://localhost:38569/static/5bfaa01f/scripts/prototype.js:106)
	at net.sourceforge.htmlunit.corejs.javascript.Interpreter.interpret(Interpreter.java:879)
	at net.sourceforge.htmlunit.corejs.javascript.InterpretedFunction.call(InterpretedFunction.java:164)
	at net.sourceforge.htmlunit.corejs.javascript.ContextFactory.doTopCall(ContextFactory.java:427)
	at com.gargoylesoftware.htmlunit.javascript.HtmlUnitContextFactory.doTopCall(HtmlUnitContextFactory.java:263)
	at net.sourceforge.htmlunit.corejs.javascript.ScriptRuntime.doTopCall(ScriptRuntime.java:3058)
	at net.sourceforge.htmlunit.corejs.javascript.InterpretedFunction.call(InterpretedFunction.java:162)
	at com.gargoylesoftware.htmlunit.javascript.JavaScriptEngine.callFunction(JavaScriptEngine.java:486)
	at com.gargoylesoftware.htmlunit.javascript.host.xml.XMLHttpRequest.setState(XMLHttpRequest.java:171)
	at com.gargoylesoftware.htmlunit.javascript.host.xml.XMLHttpRequest.doSend(XMLHttpRequest.java:445)
	at com.gargoylesoftware.htmlunit.javascript.host.xml.XMLHttpRequest.access$000(XMLHttpRequest.java:61)
	at com.gargoylesoftware.htmlunit.javascript.host.xml.XMLHttpRequest$1$1.run(XMLHttpRequest.java:393)
	at net.sourceforge.htmlunit.corejs.javascript.Context.call(Context.java:529)
	at net.sourceforge.htmlunit.corejs.javascript.ContextFactory.call(ContextFactory.java:536)
	at com.gargoylesoftware.htmlunit.javascript.host.xml.XMLHttpRequest$1.execute(XMLHttpRequest.java:390)
	at com.gargoylesoftware.htmlunit.javascript.JavaScriptEngine.processPostponedActions(JavaScriptEngine.java:556)
	at com.gargoylesoftware.htmlunit.javascript.JavaScriptEngine.access$300(JavaScriptEngine.java:68)
	at com.gargoylesoftware.htmlunit.javascript.JavaScriptEngine$HtmlUnitContextAction.run(JavaScriptEngine.java:523)
Caused by: net.sourceforge.htmlunit.corejs.javascript.NativeError$NativeErrorException: Cannot read property "parentNode" from null
	at net.sourceforge.htmlunit.corejs.javascript.NativeError.make(NativeError.java:99)
	at net.sourceforge.htmlunit.corejs.javascript.NativeGlobal.execIdCall(NativeGlobal.java:242)
	at net.sourceforge.htmlunit.corejs.javascript.IdFunctionObject.call(IdFunctionObject.java:129)
	at net.sourceforge.htmlunit.corejs.javascript.BaseFunction.construct(BaseFunction.java:349)
	at net.sourceforge.htmlunit.corejs.javascript.Context.newObject(Context.java:1541)
	at net.sourceforge.htmlunit.corejs.javascript.ScriptRuntime.newCatchScope(ScriptRuntime.java:3258)
	at script.(http://localhost:38569/static/5bfaa01f/scripts/prototype.js:450)
	at script.(http://localhost:38569/static/5bfaa01f/scripts/prototype.js:494)
	at script.findElementsBySelector(http://localhost:38569/static/5bfaa01f/scripts/behavior.js:187)
	at script.apply(http://localhost:38569/static/5bfaa01f/scripts/behavior.js:71)
	at script.(http://localhost:38569/static/5bfaa01f/scripts/behavior.js:79)
	at script.(http://localhost:38569/static/5bfaa01f/scripts/prototype.js:676)
	at script.(http://localhost:38569/static/5bfaa01f/scripts/behavior.js:68)
	at script.(http://localhost:38569/static/5bfaa01f/scripts/hudson-behavior.js:1518)
	at script.(http://localhost:38569/static/5bfaa01f/scripts/prototype.js:1122)
Caused by: net.sourceforge.htmlunit.corejs.javascript.EcmaError: TypeError: Cannot read property "parentNode" from null (http://localhost:38569/static/5bfaa01f/scripts/behavior.js#134)
	at net.sourceforge.htmlunit.corejs.javascript.ScriptRuntime.constructError(ScriptRuntime.java:3652)
	at net.sourceforge.htmlunit.corejs.javascript.ScriptRuntime.constructError(ScriptRuntime.java:3630)
	at net.sourceforge.htmlunit.corejs.javascript.ScriptRuntime.typeError(ScriptRuntime.java:3658)
	at net.sourceforge.htmlunit.corejs.javascript.ScriptRuntime.typeError2(ScriptRuntime.java:3677)
	at net.sourceforge.htmlunit.corejs.javascript.ScriptRuntime.undefReadError(ScriptRuntime.java:3690)
	at net.sourceforge.htmlunit.corejs.javascript.ScriptRuntime.getObjectProp(ScriptRuntime.java:1422)
	at script.isAncestor(http://localhost:38569/static/5bfaa01f/scripts/behavior.js:134)
	at script.(http://localhost:38569/static/5bfaa01f/scripts/behavior.js:187)
	at script.(http://localhost:38569/static/5bfaa01f/scripts/prototype.js:495)
	at script.(http://localhost:38569/static/5bfaa01f/scripts/prototype.js:451)
	at script.(http://localhost:38569/static/5bfaa01f/scripts/prototype.js:676)
JavaScriptException value = TypeError: Cannot read property "parentNode" from null