That's interesting. I've added FE before but never tried to parse through it. I would have thought it to be just an array of arrays with string[]. This works for me: var fe = customrecord_subSearchObj.filterExpression; // add the customer filter fe.push('and'); fe.push(customerFilter); // add the process date filters fe.push('and'); fe.push(["custrecord_sub_process_date","within",startDate,endDate]);