Shoutbox

What about this? I think it's much more useful to store the time rather than counting the time yourself.
I also implemented a workaround for a possible problem: when the AFK message is sent, it'll trigger the OnEvent_ChatWndReceiveMessage event and thus launching an infinite loop of AFK messages!

js code:

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var bAway = false;
var bOwnMessage = false;
var nCounterTime;

function OnEvent_ChatWndSendMessage( pChatWnd, sMessage ){
    if ( sMessage === '/counter' ) {
        if ( bAway === true ) {
            bAway = false;
        } else {
            bAway = true;
            nCounterTime = new Date().getTime();
        }
        return false;
    }

    bOwnMessage = true;
    MsgPlus.AddTimer( 'OwnMessage', 1000);
}

function OnEvent_ChatWndReceiveMessage( pChatWnd, sMessage, sOrigin, nMessageKind ){
    if ( bOwnMessage ) {
        bOwnMessage = false;
        MsgPlus.CancelTimer( 'OwnMessage' );
        return;
    }
    if( bAway ) {
        pChatWnd.SendMessage( 'I have been away from the computer for: '+parseTime( )+'.' );
    }
}

function OnEvent_Timer( sTimerId ) {
    if( sTimerId === "OwnMessage" ) {
        bOwnMessage = false;
    }
}

function parseTime( ){
    var nSeconds = Math.floor( ( new Date().getTime() - nCounterTime ) / 1000 );
    var s = nSeconds % 1000;
    var m = Math.floor( nSeconds / 60 ) % 60;
    var h = Math.floor( nSeconds / (60 * 60) );
   
    return h+'hours, '+m+'minutes and '+s+' seconds';
}

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