I count characters using NobleCount and the following code:

$('#message').NobleCount('#messageInfo',{
            max_chars: getMaxChars(),
            on_negative: function(t_obj, char_area, c_settings, char_rem){

            }
});

I want a feature like counting SMS, if the limit is reached the next 160 chars are for the second sms and so on. I can use parameters like on_update, on_positive, on_negative and block_negative.

I tried something using modulo but it does not work. Any ideas?

Firstly, character counting is very easy. You just need to use the length property on a string. To count the number of SMS messages needed, you'll need to divide by 160 and round up (because 161 characters requires 2 messages). Your code should probably look something like this:

HTML:

<textarea name="message" value="" id="message"></textarea>
<p>
    <span id="remaining">160 characters remaining</span>
    <span id="messages">1 message(s)</span>
</p>

jQuery:

$(document).ready(function(){
    var $remaining = $('#remaining'),
        $messages = $remaining.next();

    $('#message').keyup(function(){
        var chars = this.value.length,
            messages = Math.ceil(chars / 160),
            remaining = messages * 160 - (chars % (messages * 160) || messages * 160);

        $remaining.text(remaining + ' characters remaining');
        $messages.text(messages + ' message(s)');
    });
});

See jsFiddle example.