在Woocommerce上的Checkout创建自定义验证JavaScript

I'm trying to create a custom (Password needs to be 6 characters or more)js validation to Account Password on Checkout pages.

By default Woocommerce in checkout.js file create your own validation and set green (OK) or red (Not OK), but I need change that validation to check if it field has 6 or more character, if not set red.

Right now always it show as green if I write something.

The issue not is the field required or not required, the issue is js validation.

I had searched and not found nothing to solve this problem.

See the picture for visual information ...

I'm using Woocommerce 3.1.0 and Wordpress 4.8.1.

I only want to display the RED line, if it’s less than 6 characters. Right now, the green line is showing regardless. Another option could be to remove the line all together.