JQuery :: Counting Characters In A Text Area (page Counter)?

I am trying to count the characters in a text area in a form for sending sms from web to phone. Bulk sms standard is: maximum sms pages are 7 i.e 1071 characters; page 1 contains 160 characters, page 2 contains 146 characters and the rest 5 pages contains 153 characters.

Here is a javascript function I wrote but it's not working

function countPage(){
var clPg1 = 160; //character limit for page 1
var clPg2 = 146; //character limit for page 2
var clOtherPg = 153; //character limit for other pages

[Code].....