how to check who is online in facebook?

In Facebook chat there is no option of status, and you only one option and that is to go online and see who is online but by doing this other friends will know that you are online and you dont want to create this situation. so in Facebook if you want to check who is online and who is not without going online , there is a application called onlinenow you can go to that and you can first see who is online and who is not and then you can change your status accordingly. you can also block users in facebook. search for the application onlinenow and then book mark it so every time at first you go to that application and then only go online.