I put ur data as
var data = { "Employees":[{"Address1":null,"Address2":null,"City":"Banglore","ContractDocPath":null,"Designation":"Field Executive","Email":"adminhq@gmail.com","EmployeeID":null,"FEZone":null,"FirstName":"Admin","IDProof":null,"IsActive":"True","IsTermConditionAccepted":null,"LastName":null,"MiddleName":null,"OfficePhone":null,"PersonalPhone":null,"PhoneNumber":null,"PostalCode":"560078","ProfileImage":null,"RoleID":"1","RoleName":"Admin","State":"KA","TypeName":"Admin","UserID":1,"UserType":"1"},{"Address1":null,"Address2":null,"City":"Banglore","ContractDocPath":null,"Designation":"Manager","Email":"adminhq@gmail.com","EmployeeID":null,"FEZone":null,"FirstName":"Admin","IDProof":null,"IsActive":"True","IsTermConditionAccepted":null,"LastName":null,"MiddleName":null,"OfficePhone":null,"PersonalPhone":null,"PhoneNumber":null,"PostalCode":"560078","ProfileImage":null,"RoleID":"1","RoleName":"Admin","State":"KA","TypeName":"Admin","UserID":1,"UserType":"1"}
]};
var returnedData = $.grep(data.Employees, function(element, index){
return element.Designation == 'Manager';
});
alert(returnedData[0].UserID + " " + returnedData[0].Designation);
alert(returnedData[returnedData.length-1].UserID + " " + returnedData[returnedData.length-1].Designation);
Plz check this and mark this answer as resolved!!!