页面加载时jQuery textarea字符倒计时

I am using a jQuery function to generate a character countdown below a textarea field for our site's users (X Characters Remaining). My form is several pages long (somewhat like a wizard) and users typically go forward and back throughout the pages. When I go back a step and reload a page that was already completed, my character countdown displays '3000 Characters Remaining'. It's not counting the number of characters on page load. If a user goes back through the forms, I would like the function to be triggered and count the number of characters that were already entered into the textarea field. I am using a jQuery function to generate a char