I'm using the example code below. It returns the field ID. How do I display the field value? Thanks

function pageInit()
{
//On page init display the currently logged in User's profile information.
// Set variables
var userName = nlapiGetUser();       
// entity id of the current user 
var userRole = nlapiGetRole();       
// id of the current user's role 
var userDept = nlapiGetDepartment(); 
// id of the current user's department 
var userLoc = nlapiGetLocation();    
// id of the current user's location 
//  Display information
alert("Current User Information" + "\n\n" +  
"Name: " + userName + "\n" +  
"Role: " + userRole + "\n" +  
"Dept: " + userDept + "\n" +  
"Loc: " + userLoc);
}