Javascript handling from java

PDFViewerFX library uses the pdf.js javascript library to read pdf documents, and just wraps it into a javaFX node.

That's why you can execute javascript code with the PDFDisplayer. For example:

   PDFDisplayer pdfDisplayer = new PDFDisplayer(new File("path/to/your/file.pdf"));
   
   //execute js
   pdfDisplayer.executeScript("document.getElementById('secondaryToolbarToggle').style.backgroundColor = 'red';");

It will produce this result:

Or

pdfDisplayer.executeScript("document.getElementById('secondaryToolbarToggle').style.backgroundColor = 'blue';");

It will produce this result:

And of course, you can execute every other js code with it.

Catch javascript logs

This library automatically catches the javascript logs and writes it to the standard output (System.out), but if you want to change the outputstream of the js logs, or you don't want to catch these logs, you can use the JSLogListener class from the com.dansoftware.pdfdisplayer package.

For example:

   JSLogListener.setOutputStream(System.err); //setting the standard error stream for js logs
   JSLogListener.setOutputStream(null); //if we don't want to catch js logs