Skrypt by omega (znajomy programista): <script>
    var passwordManager = {

    checkPasswordStrength: function(){
        var password = document.getElementById("password").value;

        if(password.length > 6 && this.checkIfStringContainsNumbers(password)){
            this.setPasswordStrength("Hasło jest silne", "green")
        }else if(password.length > 6){
            this.setPasswordStrength("Hasło jest średnie", "blue");
        }else if(password.length >= 4 && password.length <= 6){
            this.setPasswordStrength("Hasło jest słabe", "yellow");
        }else if(password.length === 0){
            this.setPasswordStrength("Hasło jest puste", "red");
        }
    },

    setPasswordStrength: function(text, color){
        document.getElementById("result").innerHTML = text.fontcolor(color);
    },

    checkIfStringContainsNumbers: function(str){
        var regex = /\d/g;
        return regex.test(t);
    }
    }

    </script>