wkhtmltopdf wait for java script effects before printing

I want to document a webpage as it appears on screen (this not print it to pdf). I found wkhtmltopdf for that purpose. I run it on windows.

However the webpage contains some java script effects. These need to be finished before the printing starts. However this option does not solve it

--javascript-delay 15000

The whole script looks like this

C:\Users\matthias>"C:\Program Files (x86)\wkhtmltopdf\bin\wkhtmltopdf.exe" --javascript-delay 15000  --page-size A4 --viewport-size 1280x1024 --load-error-handling ignore mysieth mysite.de.pdf