Based on given requirements.
The class can be used on pages where user enter a (new) password. Just bind it to an input field. The user gets a visual help how to improve the password.
Or you can calculate a score of a given password string.
The class can be customized:
You can set custom requirements (i.e. length or count of required chars of a type).
It is ready for multi language support: you can override the texts.
Use css to customize visual output.
There is no other dependency to other frameworks (like jQuery).
A basic example ... here is an input field for a password.
Type something :-) ... you see which chracter types you already use.
to see what is needed to add this to your website.