Why do I end up getting a ton of "css error , error in expression" errors ?

The report provides a Java HtmlUnit example and CSS parser warnings, but names no HtmlUnit source files or tests. Start by locating CSS error handling and JavaScript/background-loading tests in the repository, then compare the reported CSS features and page behavior with HtmlUnit’s supported browser behavior. Done means the issue’s cause is identified and the expected handling or limitation is documented or covered by a focused test.

Hi

Ok I am basically trying to load and ultimately save the source code of a website which uses javascript for showing a result. The webpage is basically an online train ticket sale page. Here is my code:

import java.io.IOException;

public class Main {
    public static void main(String[] args) throws IOException, InterruptedException {
        System.out.println(Auxiliary.UrlToText("https://www.alibaba.ir/train/THR-MHD?adult=1&child=0&infant=0&ticketType=Family&isExclusive=false&departing=1403-12-21"));
    }
}

import org.htmlunit.BrowserVersion;
import org.htmlunit.WebClient;
import org.htmlunit.html.HtmlPage;

import java.io.IOException;

public class Auxiliary {


    public static String UrlToText(String url) throws IOException, InterruptedException {
        WebClient client1;
        client1 = new WebClient(BrowserVersion.FIREFOX);
        client1.getOptions().setJavaScriptEnabled(true);
        client1.getOptions().setCssEnabled(true);
        client1.getOptions().setRedirectEnabled(true);
        client1.getOptions().setThrowExceptionOnFailingStatusCode(false);
        client1.getOptions().setThrowExceptionOnScriptError(false);
        client1.waitForBackgroundJavaScriptStartingBefore(10000);
        return GetSource(WebClinetToHtmlpage(client1,url));
    }

    public static String GetSource(HtmlPage page) {
       String Sourcereturned = page.asXml();
       return Sourcereturned;
    }

    public static HtmlPage WebClinetToHtmlpage(WebClient client, String url) throws IOException {
        return client.getPage(url);
    }
}

When I try to get the final source code of the page, I get the following result. Which differs from when you naturally load it in a browser. In a sense, it fails to show the final ticket list that the webpage normally shows in a browser after loading JavaScript. I get a ton of css error in the final source code of the page.
What is the main culprit behind all these CSS errors and why does it fail to show the final source of the page, as a web browser such as that of Chrome or Mozilla does after the page is fully loaded?
Here is the output which I get as the source code of the page.

`"C:\Program Files\Java\jdk-23\bin\java.exe" "-javaagent:C:\Program Files\JetBrains\IntelliJ IDEA 2024.3\lib\idea_rt.jar=53674:C:\Program Files\JetBrains\IntelliJ IDEA 2024.3\bin" -Dfile.encoding=UTF-8 -Dsun.stdout.encoding=UTF-8 -Dsun.stderr.encoding=UTF-8 -classpath "C:\Users\home\IdeaProjects\BuyTicket\out\production\BuyTicket;C:\Users\home\Downloads\htmlunit-4.10.0-OSGi.jar;C:\Users\home\Downloads\htmlunit-4.10.0-bin.zip;C:\Users\home\Downloads\htmlunit-4.10.0-src.zip;C:\Users\home\Downloads\Just a Baby_ Become a parent_23.12.0_APKPure (1).apk" Main
Feb 25, 2025 9:16:16 AM org.htmlunit.DefaultCssErrorHandler error
WARNING: CSS error: 'https://cdn.alibaba.ir/h2/desktop/assets/filterscontainer-6ea81484.css' [1:632] Error in expression. (Invalid token "0". Was expecting one of: , ")", ",".)
Feb 25, 2025 9:16:16 AM org.htmlunit.DefaultCssErrorHandler error
WARNING: CSS error: 'https://cdn.alibaba.ir/h2/desktop/assets/cmsloadingbanner-f3e78277.css' [1:814] Error in expression. (Invalid token "0". Was expecting one of: , ")", ",".)
Feb 25, 2025 9:16:16 AM org.htmlunit.DefaultCssErrorHandler error
WARNING: CSS error: 'https://cdn.alibaba.ir/h2/desktop/assets/cmsloadingbanner-f3e78277.css' [1:1138] Error in expression. (Invalid token "0". Was expecting one of: , ")", ",".)
Feb 25, 2025 9:16:16 AM org.htmlunit.DefaultCssErrorHandler error
WARNING: CSS error: 'https://cdn.alibaba.ir/h2/desktop/assets/cmsloadingbanner-f3e78277.css' [1:2360] Error in expression. (Invalid token "(". Was expecting one of: , "only", , "inherit", "none", "from", , , "-", "+", , , , , , , , , , <LENGTH_PX>, <LENGTH_CM>, <LENGTH_MM>, <LENGTH_IN>, <LENGTH_PT>, <LENGTH_PC>, <LENGTH_Q>, <ANGLE_DEG>, <ANGLE_RAD>, <ANGLE_GRAD>, <ANGLE_TURN>, <TIME_MS>, <TIME_S>, <FREQ_HZ>, <FREQ_KHZ>, <RESOLUTION_DPI>, <RESOLUTION_DPCM>, , , <UNICODE_RANGE>, , <FUNCTION_CALC>, <FUNCTION_VAR>, <FUNCTION_RGB>, <FUNCTION_HSL>, <FUNCTION_HWB>, <FUNCTION_LAB>, <FUNCTION_LCH>, , "progid:".)
Feb 25, 2025 9:16:16 AM org.htmlunit.DefaultCssErrorHandler error
WARNING: CSS error: 'https://cdn.alibaba.ir/h2/desktop/assets/cmsloadingbanner-f3e78277.css' [1:2438] Error in expression. (Invalid token "(". Was expecting one of: , "only", , "inherit", "none", "from", , , "-", "+", , , , , , , , , , <LENGTH_PX>, <LENGTH_CM>, <LENGTH_MM>, <LENGTH_IN>, <LENGTH_PT>, <LENGTH_PC>, <LENGTH_Q>, <ANGLE_DEG>, <ANGLE_RAD>, <ANGLE_GRAD>, <ANGLE_TURN>, <TIME_MS>, <TIME_S>, <FREQ_HZ>, <FREQ_KHZ>, <RESOLUTION_DPI>, <RESOLUTION_DPCM>, , , <UNICODE_RANGE>, , <FUNCTION_CALC>, <FUNCTION_VAR>, <FUNCTION_RGB>, <FUNCTION_HSL>, <FUNCTION_HWB>, <FUNCTION_LAB>, <FUNCTION_LCH>, , "progid:".)
Feb 25, 2025 9:16:16 AM org.htmlunit.DefaultCssErrorHandler error
WARNING: CSS error: 'https://cdn.alibaba.ir/h2/desktop/assets/index-83bb579d.css' [1:54369] Error in expression. (Invalid token "0". Was expecting one of: , ")", ",".)
Feb 25, 2025 9:16:16 AM org.htmlunit.DefaultCssErrorHandler error
WARNING: CSS error: 'https://cdn.alibaba.ir/h2/desktop/assets/index-83bb579d.css' [1:54613] Error in expression. (Invalid token "0". Was expecting one of: , ")", ",".)
Feb 25, 2025 9:16:16 AM org.htmlunit.DefaultCssErrorHandler error
WARNING: CSS error: 'https://cdn.alibaba.ir/h2/desktop/assets/index-83bb579d.css' [1:96262] Error in pseudo class or element. (Invalid token ".". Was expecting one of: , "and", "only", , "inherit", "none", "from", , , "-", "+", .)
Feb 25, 2025 9:16:16 AM org.htmlunit.DefaultCssErrorHandler warning
WARNING: CSS warning: 'https://cdn.alibaba.ir/h2/desktop/assets/index-83bb579d.css' [1:96262] Ignoring the whole rule.
Feb 25, 2025 9:16:16 AM org.htmlunit.DefaultCssErrorHandler error
WARNING: CSS error: 'https://cdn.alibaba.ir/h2/desktop/assets/index-83bb579d.css' [1:96438] Error in pseudo class or element. (Invalid token ".". Was expecting one of: , "and", "only", , "inherit", "none", "from", , , "-", "+", .)
Feb 25, 2025 9:16:16 AM org.htmlunit.DefaultCssErrorHandler warning
WARNING: CSS warning: 'https://cdn.alibaba.ir/h2/desktop/assets/index-83bb579d.css' [1:96438] Ignoring the whole rule.
Feb 25, 2025 9:16:16 AM org.htmlunit.DefaultCssErrorHandler error
WARNING: CSS error: 'https://cdn.alibaba.ir/h2/desktop/assets/index-83bb579d.css' [1:96580] Error in pseudo class or element. (Invalid token ".". Was expecting one of: , "and", "only", , "inherit", "none", "from", , , "-", "+", .)
Feb 25, 2025 9:16:16 AM org.htmlunit.DefaultCssErrorHandler warning
WARNING: CSS warning: 'https://cdn.alibaba.ir/h2/desktop/assets/index-83bb579d.css' [1:96580] Ignoring the whole rule.
Feb 25, 2025 9:16:16 AM org.htmlunit.DefaultCssErrorHandler error
WARNING: CSS error: 'https://cdn.alibaba.ir/h2/desktop/assets/index-83bb579d.css' [1:96759] Error in pseudo class or element. (Invalid token ".". Was expecting one of: , "and", "only", , "inherit", "none", "from", , , "-", "+", .)
Feb 25, 2025 9:16:16 AM org.htmlunit.DefaultCssErrorHandler warning
WARNING: CSS warning: 'https://cdn.alibaba.ir/h2/desktop/assets/index-83bb579d.css' [1:96759] Ignoring the whole rule.
Feb 25, 2025 9:16:16 AM org.htmlunit.DefaultCssErrorHandler error
WARNING: CSS error: 'https://cdn.alibaba.ir/h2/desktop/assets/index-83bb579d.css' [1:96851] Error in pseudo class or element. (Invalid token ".". Was expecting one of: , "and", "only", , "inherit", "none", "from", , , "-", "+", .)
Feb 25, 2025 9:16:16 AM org.htmlunit.DefaultCssErrorHandler warning
WARNING: CSS warning: 'https://cdn.alibaba.ir/h2/desktop/assets/index-83bb579d.css' [1:96851] Ignoring the whole rule.
Feb 25, 2025 9:16:16 AM org.htmlunit.DefaultCssErrorHandler error
WARNING: CSS error: 'https://cdn.alibaba.ir/h2/desktop/assets/index-83bb579d.css' [1:102936] Error in expression. (Invalid token "env(". Was expecting one of: , "and", "only", , "inherit", "none", "from", , "(", "-", "+", , , , , , , , , <LENGTH_PX>, <LENGTH_CM>, <LENGTH_MM>, <LENGTH_IN>, <LENGTH_PT>, <LENGTH_PC>, <LENGTH_Q>, <ANGLE_DEG>, <ANGLE_RAD>, <ANGLE_GRAD>, <ANGLE_TURN>, <TIME_MS>, <TIME_S>, <FREQ_HZ>, <FREQ_KHZ>, <RESOLUTION_DPI>, <RESOLUTION_DPCM>, , <FUNCTION_CALC>, <FUNCTION_VAR>.)
Feb 25, 2025 9:16:16 AM org.htmlunit.DefaultCssErrorHandler error
WARNING: CSS error: 'https://cdn.alibaba.ir/h2/desktop/assets/index-83bb579d.css' [1:114732] Error in expression. (Invalid token "-". Was expecting one of: , <CUSTOM_PROPERTY_NAME>.)
Feb 25, 2025 9:16:16 AM org.htmlunit.DefaultCssErrorHandler error
WARNING: CSS error: 'https://cdn.alibaba.ir/h2/desktop/assets/index-83bb579d.css' [1:114761] Error in expression. (Invalid token "-". Was expecting one of: , <CUSTOM_PROPERTY_NAME>.)
Feb 25, 2025 9:16:16 AM org.htmlunit.DefaultCssErrorHandler error
WARNING: CSS error: 'https://cdn.alibaba.ir/h2/desktop/assets/index-83bb579d.css' [1:114787] Error in expression. (Invalid token "-". Was expecting one of: , <CUSTOM_PROPERTY_NAME>.)
Feb 25, 2025 9:16:16 AM org.htmlunit.DefaultCssErrorHandler error
WARNING: CSS error: 'https://cdn.alibaba.ir/h2/desktop/assets/index-83bb579d.css' [1:114814] Error in expression. (Invalid token "-". Was expecting one of: , <CUSTOM_PROPERTY_NAME>.)
Feb 25, 2025 9:16:16 AM org.htmlunit.DefaultCssErrorHandler error
WARNING: CSS error: 'https://cdn.alibaba.ir/h2/desktop/assets/index-83bb579d.css' [1:114847] Error in expression. (Invalid token "-". Was expecting one of: , <CUSTOM_PROPERTY_NAME>.)
Feb 25, 2025 9:16:16 AM org.htmlunit.DefaultCssErrorHandler error
WARNING: CSS error: 'https://cdn.alibaba.ir/h2/desktop/assets/index-83bb579d.css' [1:174886] Error in expression. (Invalid token "0". Was expecting one of: , ")", ",".)
Feb 25, 2025 9:16:16 AM org.htmlunit.DefaultCssErrorHandler error
WARNING: CSS error: 'https://cdn.alibaba.ir/h2/desktop/assets/index-83bb579d.css' [1:239736] Error in expression. (Invalid token "0". Was expecting one of: , ")", ",".)
Feb 25, 2025 9:16:16 AM org.htmlunit.DefaultCssErrorHandler error
WARNING: CSS error: 'https://cdn.alibaba.ir/h2/desktop/assets/index-83bb579d.css' [1:239984] Error in expression. (Invalid token "0". Was expecting one of: , ")", ",".)
Feb 25, 2025 9:16:16 AM org.htmlunit.DefaultCssErrorHandler error
WARNING: CSS error: 'https://cdn.alibaba.ir/h2/desktop/assets/index-83bb579d.css' [1:240306] Error in expression. (Invalid token "0". Was expecting one of: , ")", ",".)
Feb 25, 2025 9:16:16 AM org.htmlunit.DefaultCssErrorHandler error
WARNING: CSS error: 'https://cdn.alibaba.ir/h2/desktop/assets/index-83bb579d.css' [1:240504] Error in expression. (Invalid token "0". Was expecting one of: , ")", ",".)
Feb 25, 2025 9:16:16 AM org.htmlunit.DefaultCssErrorHandler error
WARNING: CSS error: 'https://cdn.alibaba.ir/h2/desktop/assets/index-83bb579d.css' [1:240768] Error in expression. (Invalid token "0". Was expecting one of: , ")", ",".)
Feb 25, 2025 9:16:16 AM org.htmlunit.DefaultCssErrorHandler error
WARNING: CSS error: 'https://cdn.alibaba.ir/h2/desktop/assets/index-83bb579d.css' [1:241016] Error in expression. (Invalid token "0". Was expecting one of: , ")", ",".)
Feb 25, 2025 9:16:16 AM org.htmlunit.DefaultCssErrorHandler error
WARNING: CSS error: 'https://cdn.alibaba.ir/h2/desktop/assets/index-83bb579d.css' [1:241266] Error in expression. (Invalid token "0". Was expecting one of: , ")", ",".)
Feb 25, 2025 9:16:16 AM org.htmlunit.DefaultCssErrorHandler error
WARNING: CSS error: 'https://cdn.alibaba.ir/h2/desktop/assets/index-83bb579d.css' [1:241466] Error in expression. (Invalid token "0". Was expecting one of: , ")", ",".)
Feb 25, 2025 9:16:16 AM org.htmlunit.DefaultCssErrorHandler error
WARNING: CSS error: 'https://cdn.alibaba.ir/h2/desktop/assets/index-83bb579d.css' [1:241722] Error in expression. (Invalid token "0". Was expecting one of: , ")", ",".)
Feb 25, 2025 9:16:16 AM org.htmlunit.DefaultCssErrorHandler error
WARNING: CSS error: 'https://cdn.alibaba.ir/h2/desktop/assets/index-83bb579d.css' [1:249276] Error in expression. (Invalid token "0". Was expecting one of: , ")", ",".)
Feb 25, 2025 9:16:16 AM org.htmlunit.DefaultCssErrorHandler error
WARNING: CSS error: 'https://cdn.alibaba.ir/h2/desktop/assets/index-83bb579d.css' [1:249665] Error in expression. (Invalid token "0". Was expecting one of: , ")", ",".)
Feb 25, 2025 9:16:16 AM org.htmlunit.DefaultCssErrorHandler error
WARNING: CSS error: 'https://cdn.alibaba.ir/h2/desktop/assets/index-83bb579d.css' [1:280999] Error in expression. (Invalid token "0". Was expecting one of: , ")", ",".)
Feb 25, 2025 9:16:16 AM org.htmlunit.DefaultCssErrorHandler error
WARNING: CSS error: 'https://cdn.alibaba.ir/h2/desktop/assets/index-83bb579d.css' [1:281251] Error in expression. (Invalid token "0". Was expecting one of: , ")", ",".)
Feb 25, 2025 9:16:16 AM org.htmlunit.DefaultCssErrorHandler error
WARNING: CSS error: 'https://cdn.alibaba.ir/h2/desktop/assets/index-83bb579d.css' [1:287414] Error in expression. (Invalid token "0". Was expecting one of: , ")", ",".)
Feb 25, 2025 9:16:16 AM org.htmlunit.DefaultCssErrorHandler error
WARNING: CSS error: 'https://cdn.alibaba.ir/h2/desktop/assets/index-83bb579d.css' [1:290284] Error in expression. (Invalid token "0". Was expecting one of: , ")", ",".)
Feb 25, 2025 9:16:16 AM org.htmlunit.DefaultCssErrorHandler error
WARNING: CSS error: 'https://cdn.alibaba.ir/h2/desktop/assets/index-83bb579d.css' [1:290827] Error in expression. (Invalid token "0". Was expecting one of: , ")", ",".)
Feb 25, 2025 9:16:16 AM org.htmlunit.DefaultCssErrorHandler error
WARNING: CSS error: 'https://cdn.alibaba.ir/h2/desktop/assets/index-83bb579d.css' [1:291286] Error in expression. (Invalid token "0". Was expecting one of: , ")", ",".)
Feb 25, 2025 9:16:16 AM org.htmlunit.DefaultCssErrorHandler error
WARNING: CSS error: 'https://cdn.alibaba.ir/h2/desktop/assets/index-83bb579d.css' [1:294889] Error in expression. (Invalid token "0". Was expecting one of: , ")", ",".)
Feb 25, 2025 9:16:16 AM org.htmlunit.DefaultCssErrorHandler error
WARNING: CSS error: 'https://cdn.alibaba.ir/h2/desktop/assets/index-83bb579d.css' [1:295435] Error in expression. (Invalid token "0". Was expecting one of: , ")", ",".)
Feb 25, 2025 9:16:16 AM org.htmlunit.DefaultCssErrorHandler error
WARNING: CSS error: 'https://cdn.alibaba.ir/h2/desktop/assets/index-83bb579d.css' [1:300357] Error in expression. (Invalid token "0". Was expecting one of: , ")", ",".)
Feb 25, 2025 9:16:16 AM org.htmlunit.DefaultCssErrorHandler error
WARNING: CSS error: 'https://cdn.alibaba.ir/h2/desktop/assets/index-83bb579d.css' [1:300676] Error in expression. (Invalid token "0". Was expecting one of: , ")", ",".)
Feb 25, 2025 9:16:16 AM org.htmlunit.DefaultCssErrorHandler error
WARNING: CSS error: 'https://cdn.alibaba.ir/h2/desktop/assets/index-83bb579d.css' [1:302450] Error in expression. (Invalid token "0". Was expecting one of: , ")", ",".)
Feb 25, 2025 9:16:16 AM org.htmlunit.DefaultCssErrorHandler error
WARNING: CSS error: 'https://cdn.alibaba.ir/h2/desktop/assets/index-83bb579d.css' [1:304423] Error in expression. (Invalid token "0". Was expecting one of: , ")", ",".)
Feb 25, 2025 9:16:16 AM org.htmlunit.DefaultCssErrorHandler error
WARNING: CSS error: 'https://cdn.alibaba.ir/h2/desktop/assets/index-83bb579d.css' [1:306174] Error in expression. (Invalid token "0". Was expecting one of: , ")", ",".)
Feb 25, 2025 9:16:16 AM org.htmlunit.DefaultCssErrorHandler error
WARNING: CSS error: 'https://cdn.alibaba.ir/h2/desktop/assets/index-83bb579d.css' [1:306429] Error in expression. (Invalid token "0". Was expecting one of: , ")", ",".)
Feb 25, 2025 9:16:16 AM org.htmlunit.DefaultCssErrorHandler error
WARNING: CSS error: 'https://cdn.alibaba.ir/h2/desktop/assets/index-83bb579d.css' [1:306725] Error in expression. (Invalid token "0". Was expecting one of: , ")", ",".)
Feb 25, 2025 9:16:16 AM org.htmlunit.DefaultCssErrorHandler error
WARNING: CSS error: 'https://cdn.alibaba.ir/h2/desktop/assets/index-83bb579d.css' [1:307563] Error in pseudo class or element. (Invalid token ".". Was expecting one of: , "and", "only", , "inherit", "none", "from", , , "-", "+", .)
Feb 25, 2025 9:16:16 AM org.htmlunit.DefaultCssErrorHandler warning
WARNING: CSS warning: 'https://cdn.alibaba.ir/h2/desktop/assets/index-83bb579d.css' [1:307563] Ignoring the whole rule.
Feb 25, 2025 9:16:16 AM org.htmlunit.DefaultCssErrorHandler error
WARNING: CSS error: 'https://cdn.alibaba.ir/h2/desktop/assets/index-83bb579d.css' [1:308021] Error in expression. (Invalid token "0". Was expecting one of: , ")", ",".)