PDF_viewHTMLPreviewAsImage form dependant. This permit to reuse it in other
forms.

"?" should not be part of the base_url

add a XXX comment : this part should be merge with OOo pagination, and should
be async

Reviewed by kazuhiko

git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@38124 20353a03-c40f-0410-a6d1-a30d3c3de9de