Caling AJAX Method for multiple hidden ids aspx
You should create a function that would wrap the ajax call and use it as many times as you wish.

var callMyMethod = function(nodeType, clientId, target) {
  var ids = $('#' + clientId).val();
  ajaxMethod('/MyPage/MyMethod', {
    custId: custId, // is it a global variable?
    vehicleNodeType: nodeType,
    selectedIds: ids 
  }, target);
};

callMyMethod('&lt;%=VechileNodeTypeEnum.Car.ToString()%&gt;', '&lt;%=hfCarId.ClientID%&gt;', '#carDiv');
callMyMethod('&lt;%=VechileNodeTypeEnum.Van.ToString()%&gt;', '&lt;%=hfVanId.ClientID%&gt;', '#vanDiv');
callMyMethod('&lt;%=VechileNodeTypeEnum.Truck.ToString()%&gt;', '&lt;%=hfTruckId.ClientID%&gt;', '#truckDiv');
callMyMethod('&lt;%=VechileNodeTypeEnum.MotorCycle.ToString()%&gt;', '&lt;%=hfMotorCycleId.ClientID%&gt;', '#motorCycleDiv');


If there is some correlation between for example hfCarId.ClientID and #carId, you can remove the target argument from the function.

It should be also possible to generate these calls by iterating over Car, Van, Truck and MotorCycle but I'm not that familiar with .net to suggest it to you.