Thanks, Manoj!
I tried adding an interval of the xValue to the Range endValue so it keeps updating to new endValue.
for example, using get and set
1.Getting the existing value of range and Add the new time interval to it.
var newInterval = new Date(chart.rangeSelector.inputFields.get(“endValue”));
newInterval.setSeconds( new interval.getSeconds() + 2 );
2.And set the new value again
stockChart.rangeSelector.inputFields.set(“endValue”,(((newInterval)))),true);
or
chart.options.rangeSelector.inputFields.endValue =newInterval;
But unfortunately, it didn’t work. Thanks anyway.