Common Editing properties -> edittype -> custom -> code example

describes function as:

function myvalue(elem)
Which is wrong. This function is called in 2 different scenario: befor submitting data, to get data from custom editor, and before showing custom 
editor to poppulate it with data.
Here is what I came up with for my application (can will be different in the wiki example context):

            function sitesGridValue(elem, operation, param) {
                switch (operation) {
                    case 'get': 
                        return $("table.ui-jqgrid-btable", elem).getRowData();
                    case 'set': 
                        return $("table.ui-jqgrid-btable", elem)[0].addJSONData(JSON.parse(param));
                }
            }
It is crucial to recognize get/set operation, otherwise you will get some unky behavior, for example, custom field does not change 
when you navigate forward/backwards.