janhancic/hn-unread-comments

//localStorage.clear (); // for testing purposes

localStorage.removeItem( 'read_comments' ); // remove old read comments storage

var unreadColour = $( 'table:first td:first' ).attr( 'bgcolor' ), // background colour of the top navigation bar
    $comments = null,
    readComments;

// get all comments on this page
if ( ( document.location + '' ).indexOf ( 'item?id=' ) > 0 ) { // we are on a item page
    $comments = $( 'body > center > table > tbody > tr:eq(2) > td table:eq(1) > tbody > tr' );
} else { // we are on threads page
    $comments = $( 'body > center > table > tbody > tr:gt(2)' );
}

readComments = localStorage.getObject( 'read_comments_list' ) || {}; // get all stored unread comments

$comments.each( function () {
    var $this = $( this ),
        commentContentMd5 = md5( $this.find( 'table td:eq(2) span.comment' ).text() );

    if ( readComments[commentContentMd5] === undefined ) {
        // mark this comments as unread
        $this.find( 'table td:eq(2)' ).css( 'border-left', '2px solid ' + unreadColour );

        readComments[commentContentMd5] = true;
    }
} );

localStorage.setObject( 'read_comments_list', readComments );