var ourGroups = gs.getUser().getMyGroups(); // this get my groups where I do belong
// ourGroups is now an array containing sys_id of each group you are a member of
var grpDisplay = ''; // for optimal javascript you should define variable outside of a loop
for ( var i=0; i < ourGroups.size(); i=i+1) // ourGroups is an array containing sys_id of groups
{
var group = new GlideRecord('sys_user_group'); // Yes, database query
group.get(ourGroups.get(i)); // Yes group.addQuery() is also valid, however requires 3 lines of code instead of this one.
grpDisplay = grpDisplay + group.name + '\r\n'; // Yes, this is building a string of Group names seperated by OS specific (Windows) new line characters
gs.addInfoMessage(grpDisplay); // Not a system message, but an info message that will appear at the top of the form the user has just loaded. gs.log() would write the output to the logs
}
