如何从SWT浏览器中加载的页面读取隐藏属性

import org.eclipse.swt.SWT;
import org.eclipse.swt.browser.Browser;
import org.eclipse.swt.browser.ProgressEvent;
import org.eclipse.swt.browser.ProgressListener;
import org.eclipse.swt.layout.FillLayout;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Shell;

public class SWTBrowserExample {

    public static void main(String[] args) {
        Display display = new Display();
        Shell shell = new Shell(display);
        shell.setLayout(new FillLayout());

        Browser browser = new Browser(shell, SWT.NONE);

        browser.addProgressListener(new ProgressListener() {
            @Override
            public void completed(ProgressEvent event) {
                // 页面加载完成时执行以下操作
                String javascriptCode = "document.getElementById('hiddenProperty').value;";
                String hiddenPropertyValue = browser.evaluate(javascriptCode);
                System.out.println("隐藏属性的值为：" + hiddenPropertyValue);
            }

            @Override
            public void changed(ProgressEvent event) {
            }
        });

        browser.setUrl("https://example.com");

        shell.open();
        while (!shell.isDisposed()) {
            if (!display.readAndDispatch()) {
                display.sleep();
            }
        }
        display.dispose();
    }
}