Possible to set the pdf export preference for "Create separate pdf file" check box in a javascript

I'm exporting a series of pdf pages using javascript and when I create the pdf it always seems to toggle that preference on and put the pdf's into a folder. I would like them to just be on the desktop but it just keeps turning it back on. Anyone know if its possible and how? My guess it would be something like this:  createSeperatePdf = false;