angular dynamic attributes for service

Given the following angularjs service:

angular.module('myApp.services', [])
  .factory('EmployeesService', ['$http', function ($http) {
      return {
          name: 'Employees Service',
          getByTerm: function (term, callback) {
              $http.get('Services/GetEmployess?term='+term).success(function (data) {
                  callback(data);
              });
          }
      };
  } ]);

How can I set the $http.get URL to be dynamic and not hard-coded?

Not sure what part of the url you want to be dynamic, so this is if you want the "term=" + term part to be dynamic:

angular.module('myApp.services', [])
    .factory('EmployeesService', ['$http', function ($http) {
        return {
        name: 'Employees Service',
        getByTerm: function (params, callback) {
                var terms = [];

                //params example: {param1: "lorem", param2:"ipsum"}
                for(var key in params){
                    if(params.hasOwnProperty(key)){
                        terms.push(key + "=" + params[key]);
                    }
                }
                //terms now looks like this: ["param1=lorem", "param2=ipsum"]

                var url = 'Services/GetEmployess?' + terms.join("&");

                //url will look lik this: 'Services/GetEmployess?param1=lorem&param1=ipsum';

                $http.get(url).success(function (data) {
                    callback(data);
                });
            }
        };
    } ]);

If you want the actual url that you're posting to be dynamic, pass it in as another parameter:

angular.module('myApp.services', [])
  .factory('EmployeesService', ['$http', function ($http) {
      return {
          name: 'Employees Service',
          getByTerm: function (url, term, callback) {
              $http.get(url+term).success(function (data) {
                  callback(data);
              });
          }
      };
  } ]);

If neither of these are what you're looking for... can you elaborate on what part of the url you want to be dynamic?