I recently started using jqgrid, adding it to one of our projects. In our project we have several prototypes defined for the Array object ( obj.contains(x), etc ). I added the grid control and it works fine, but when I added the grouping module with summary footers it returns an error “jqGrid – No such method: groupingCalculations.undefined”. I basically have a few records with the Summary Footers, since we need aggregates for several fields: