Rhino not compiling any JavaScript when ScriptException encountered

[sandeep-dfe]

eg if javascript is pulled from a file such as

then htmlunit driver does not find the javascript function referenced on the html page, ie I get error such as :

"org.htmlunit.ScriptException: ReferenceError: "updateNumberOfSchemes" is not defined. "

Even though "webClient.getOptions().setJavaScriptEnabled(true)"

[rbri]

@sandeep-dfe Hmm, sounds strange - maybe there is another reason for that. Do you have a (public) website where i can try to reproduce that?

[sandeep-dfe]

Hi @rbri

try driver.get("https://find-employer-schemes.education.gov.uk/");

this gives

eg [pool-1-thread-1] [ERROR] o.h.j.DefaultJavaScriptErrorListener Error during JavaScript execution org.htmlunit.ScriptException: ReferenceError: "sortSchemes" is not defined.

Chromedriver does not have this problem

[rbri]

sorry but i can't reproduce this. Can you please make a complete sample class.

[sandeep-dfe]

htmlunit-js-error.zip

Hi @rbri Please review javascriptIssueDemo in the attachment, thanks.

[rbri]

@sandeep-dfe OK, another limitation of the rhino (core-js) engine.

at the beginning of the log output you will see the reason:

org.htmlunit.ScriptException: TypeError: redeclaration of var i. (https://find-employer-schemes.education.gov.uk/js/site.js?v=rG3nlLugPDi7jE4PNwDK7S4obbQ#1)

Because of this error the whole js code not compile and therefore you miss the function.

At the moment you can only patch the js code on the fly.

Please implement your own ScriptPreProcessor (see https://github.com/HtmlUnit/htmlunit/blob/master/src/main/java/org/htmlunit/javascript/preprocessor/HtmxOneNineTenScriptPreProcessor.java as sample).

the important part should look like

@Override
public String preProcess(final HtmlPage htmlPage, final String sourceCode, final String sourceName,
        final int lineNumber, final HtmlElement htmlElement) {

    String patchedSourceCode = sourceCode;

    if (sourceName.contains("/site.js") && !sourceName.contains("/site.js#")) {
        patchedSourceCode = StringUtils.replace(
                sourceCode,
                "var t=this,i=t.getAttribute(\"data-menu-section\");const n=document.querySelector('.govuk-header__navigation-item[data-menu-section=\"'+i+'\"]');",
                "var t=this,ix=t.getAttribute(\"data-menu-section\");const n=document.querySelector('.govuk-header__navigation-item[data-menu-section=\"'+ix+'\"]');");
    }

    if (nextScriptPreProcessor_ != null) {
        return nextScriptPreProcessor_.preProcess(htmlPage, patchedSourceCode, sourceName, lineNumber, htmlElement);
    }

    return patchedSourceCode;
}

This replaces the declaration of var i at one place - to avoid the re declaration error.

Attach the preprocessor to your client and your code should run.

            webClient.setScriptPreProcessor(new ...ScriptPreProcessor());

[sandeep-dfe]

Thanks for the guidance @rbri

[sandeep-dfe]

@rbri I've closed this issue however as the suggestion is more of a workaround, it it be better if the issue remained open until a fix found?