passing POST params to a PDF

passing POST params to a PDF

Hi,
I'll try to explain my problem ...

I have several form inputs with a submit link in a modal page, and when I click the submit link I call this function to download a personalized pdf with the GET params.
  1. function descargar(){
  2.     window.parent.document.location = "admin.php?controlador=Cat&accion=descargarPDF&titulo=" + $("#titulo").val() + "&autor=" + $("#autor").val() + "&comentario=" + $("#comentario").val();
  3. }
This works.

Now, I need to pass an undefined number of params, and I prefer do this thru POST, but I have no idea to code this. I've searched similar scripts but I didn't find nothing.

Anyone can help me? Thanks.
Toni.