Ghost mode for Facebook

Method 1: Block requests to these urls

Hide online status

*://edge-chat.facebook.com/*
*://0-edge-chat.facebook.com/*
*://1-edge-chat.facebook.com/*
*://2-edge-chat.facebook.com/*
*://3-edge-chat.facebook.com/*
*://4-edge-chat.facebook.com/*
*://5-edge-chat.facebook.com/*
*://6-edge-chat.facebook.com/*
*://7-edge-chat.facebook.com/*
*://8-edge-chat.facebook.com/*
*://9-edge-chat.facebook.com/*
*://www.facebook.com/ajax/chat/*
*://www.facebook.com/chat/*
*://www.facebook.com/ajax/presence/*
*://edge-chat.messenger.com/*
*://0-edge-chat.messenger.com/*
*://1-edge-chat.messenger.com/*
*://2-edge-chat.messenger.com/*
*://3-edge-chat.messenger.com/*
*://4-edge-chat.messenger.com/*
*://5-edge-chat.messenger.com/*
*://6-edge-chat.messenger.com/*
*://7-edge-chat.messenger.com/*
*://8-edge-chat.messenger.com/*
*://9-edge-chat.messenger.com/*
*://www.messenger.com/ajax/chat/*
*://www.messenger.com/chat/*
*://www.messenger.com/ajax/presence/*

Hide typing indicator

*://*.facebook.com/*typ.php*
*://*.messenger.com/*typ.php*

Hide seen

*://*.facebook.com/*change_read_status*
*://*.facebook.com/*mark_seen*
*://*.messenger.com/*change_read_status*
*://*.messenger.com/*mark_seen*

Method 2: Use extension (Chrome)

Extension "Silence is Golden" for Google Chrome.