As such last seen option is very helpful feature of chat box. But sometimes it becomes a problem for you. Sometimes you did not want to reply to your friends message. Earlier you can skip the conversation and can pretend that you did not saw the message but now with this seen option , your friend will notify about your last seen with time. So if you are thinking to ignore, then you can not lie. But don’t worry there are tricks to disable seen option of Facebook chat.

To disable Facebook seen option, you need to install the Browser extension. Or you can do it manually by blocking some URL.

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How to Disable FB Seen Option on Google Chrome

On chrome there is a simple browser extension available to disable last seen of Facebook. You just need to download and install this extension.

It is simple and light add on that allow user to control his/her Facebook seen option. It allow you to manually control the seen option, so that you can select whom you want to show your last seen.

disable fb seen option
To install this simply click on +Free button and in popup confirm it by clicking on ADD.

This is a powerful browser extension to disable seen feature of facebook and preventing your friend to know that you read the message. With seen option you can also block the typing.. option with this coll add on. 
It gives you control to mark any message as read when you want with a simple mark as a read button in your chat box.

How to Disable FB Seen Option on Mozilla Firefox

On Firefox you can either use manual method or add on for this.

Add On method

How to Disable FB Seen Option on other browser

In other browsers you just need to block this below url to disable fb seen option.
/ajax/mercury/change_read_status.php$domain=facebook.com
Disabling the FB seen option is very easy with these powerful extensions. If you still face any problem you can ask it in comments