I'm working on a website with a sign-up form. I've been able to perform validation without page reload, printing appropriate error messages.However i'm trying to implement an interface i've seen on a couple of websites, where a user is guided to fill certain fields like password that come with restrictions, as shown in the attached image (the nice blue guide on the right). I tried to 'inspect element' on pages where i've seen this but i wasnt able to decipher the code. How can i implement such fucntionality or where can i learn to do so. Thank you in advance.