In the filter listener function
listeners: [{ 'change': function (evt, ui) {
var val = ui.value; //e.g., '03/01/2017', user chosen date.
grid.filter({
data: [
{dataIndx: 'startDate', condition: 'lte', value: val },
{ dataIndx: 'endDate', condition: 'gte', value: val }
]
})
}}]