Getting the extension of a file

System

Hi all,

I trying to detect the extension of the file when you clic over the link of a folder in worksite web.

What I would like to do is if it is xml open in the fram and for the rest, open in a new window.

In the common.js you have the following function:

function Description_OnAnchorClick(objectType, nrtid, id, partID, parentID)

which controls the opening proccess of the doc, you have the following part:

switch ( objectType )
{
case 'imTypeDocument':
downloadEx(nrtid, page.documentOption, DocumentTarget.NewWindow);
break;

What I would like to do is:
//*******************************************
If (extension == 'xml')
{
downloadEx(nrtid, page.documentOption, DocumentTarget.Frame);

}
else
{
downloadEx(nrtid, page.documentOption, DocumentTarget.NewWindow);

}
//*****************************************

Does anybody know how to handle the extension of the doc inside this library?

Thanks in advance
Javi