Error message when server does not return JSON structure.
String, default = 'Returned data is not in valid JSON format.'
If you do not like default message, you are welcome to define your own. $('#grid').w2grid({ name : 'grid', msgNotJSON: 'Give me JSON!', columns: [ { field: 'recid', caption: 'ID', size: '50px' }, { field: 'lname', caption: 'Last Name', size: '30%' }, { field: 'fname', caption: 'First Name', size: '30%' }, { field: 'email', caption: 'Email', size: '40%' }, { field: 'sdate', caption: 'Start Date', size: '120px' }, { field: 'sdate', caption: 'End Date', size: '120px' } ] }); You can also overwrite this message in prototype, then all grids will have same message: w2obj.grid.prototype.msgNotJSON = 'Give me JSON!';