I want to convert html display contents to PDF

As for Javascript, the library jsPDF seems to support PDF generation from DOM elements.However, if you look at HTML Renderer in the sample on the site, it seems that CSS does not apply.

You can use html2canvas, etc. to convert it into an image and embed it in a PDF.

• Create PDF with Javascript - Flying

For PHP, there are ways to use PHP's library from HTML analysis, such as dompdf and tcpdf, and PhantomJS and wkhtmltopdf using browser rendering engines.In the latter case, the program must be installed separately from PHP, so it may be difficult for rental servers.

• How do I output PDFs in php-zend framework 2?- Stack overflow
• Fight wkhtmltopdf+snappy when creating PDFs in PHP - Qiita

You can convert from Html to PDF in Java, and you can easily complete it with components such as Spire.PDF for Java.

import com.spire.pdf.graphics.PdfMargins;
import com.spire.pdf.htmlconverter.qt.HtmlConverter;
import com.spire.pdf.htmlconverter.qt.Size;

public class HtmltoPDF
{
    public static void main (String[]args)
    {
        // define the HTML link and result PDF
        String url="https://www.xxxxxxx.com/";
        String fileName = "Result.pdf";
        // Set the plugin path
        String pluginPath="D:/Qt/plugins_32";
        HtmlConverter.setPluginPath(pluginPath);
        // convert HTML to PDF and set the size of the result PDF page
        HtmlConverter.convert(url,fileName,true,1000000,newSize(600f,900f),new PdfMargins(0));
    }
}

That's all you need, and you can convert other formats.