Ext.DomHelper.append and vvIn_JSON ?

[mwmayer4]

I have a working Ajax.request that receives as one of it's parms a JSON string of params so that on the back-end, this works:
vvIn.variableName = 'imagelist';
vvIn.fieldName = 'imageid';
vvIn.totalSize = %size(imageIDs:*all);
vvIn.elementSize = %size(ImageIDs);
numElements = vvIn_JSON(vvIn:%addr(ImageIDs));

the result of the Ajax request creates a PDF file on the IFS and returns the path to it so that I can show it in a window.

Instead, I need to to create the ability to "download" the PDF. I have done this using Ext.DomHelper, but....
I can't figure out how to pass in the parm that is an array encoded in JSON using Ext.encode(array)

I'm trying to use the following:

Ext.DomHelper.append(document.body, {
tag: 'iframe',
frameBorder: 0,
width: 0,
height: 0,
css: 'display:none;visibility:hidden;height:1px;',
src: 'vvcall.pgm?sid=' + sessionStorage.sid + '&app=' + Ext.getUrlParam('app') + '&pgm=mcbcivil&action=getMultiView&imagelist=' + imageIDs + '&casenbr=' + casenbr
});

the imagelist parm is an array and, of course, it doesn't work.

can this be done? must be an "advance technique" ;)