You can restrict the number of character input in any textarea or input box.This plugin checks not only input by keyboard but also pasting any text by mouse it shows remaining char counting (optional) .There are more settings
Download: https://github.com/rothy1248/charlimit
Demonstration: https://github.com/rothy1248/charlimit
Plugin homepage: https://github.com/rothy1248/charlimit
Implementation:
$('.charlimit2').charlimit()
$('.charlimit2').charlimit({
'limit':15,
'this_class':'democlass',
'color':1,
'disable':1,
'position':'before'
});