There is a new control in sharepoint 2013 named ClientPeoplePicker.Which is a very good control loads the user prediction on the client side using a hidden div .
To get the data from this control on the server side use the code below
string a = "";
To get the data from this control on the server side use the code below
string a = "";
ArrayList resolve = pepPickcker.ResolvedEntities;
foreach (PickerEntity entity in resolve){
a += entity.Key+";"; //Key will give you the login name you can use other attributes}
*pepPickcker is the control ID