setDefaultWorkbookFormat - cfsimplicity/spreadsheet-cfml GitHub Wiki
For the current spreadsheet library instance, sets the default type of workbook returned by the new() method.
setDefaultWorkbookFormat( format )
Required arguments
formatstring: one of the following:binary,xls,xml,xlsx.
Example
spreadsheet = New spreadsheet();
spreadsheet.setDefaultWorkbookFormat( "xml" );
workbook = spreadsheet.new(); //returns an "xlsx" workbook object