JAVASCRIPT

Javascript validate password

let pattern = new RegExp("^(?=(.*[a-zA-Z]){1,})(?=(.*[0-9]){2,}).{8,}$"); //Regex: At least 8 characters with at least 2 numericals
    let inputToListen = document.getElementById('pass-one'); // Get Input where psw is write
    let valide = document.getElementsByClassName('indicator')[0]; //little indicator of validity of psw

    inputToListen.addEventListener('input', function () { // Add event listener on input
        if(pattern.test(inputToListen.value)){
            valide.innerHTML = 'ok';
        }else{
            valide.innerHTML = 'not ok'
        }
    });

validate password javascript

// Commonly used regular expression

// Check 2-9 characters, false if not matched, true if matched
const validateName = (name) => {
   const reg = /^[u4e00-u9fa5]{2,9}$/;
   return reg.test(name);
};
// Verify phone number
const validatePhoneNum = (mobile) => {
   const reg = /^1[3,4,5,6,7,8,9]d{9}$/;
   return reg.test(mobile);
};
// Check passwords consisting of 6 to 18 uppercase and lowercase alphanumeric underscores
const validatePassword = (password) => {
   const reg = /^[a-zA-Z0-9_]{6,18}$/;
   return reg.test(password);
};

js password check

var code = document.getElementById("password");

var strengthbar = document.getElementById("meter");
var display = document.getElementsByClassName("textbox")[0];

code.addEventListener("keyup", function() {
  checkpassword(code.value);
});


function checkpassword(password) {
  var strength = 0;
  if (password.match(/[a-z]+/)) {
    strength += 1;
  }
  if (password.match(/[A-Z]+/)) {
    strength += 1;
  }
  if (password.match(/[0-9]+/)) {
    strength += 1;
  }
  if (password.match(/[$@#&!]+/)) {
    strength += 1;

  }

  if (password.length < 6) {
    display.innerHTML = "minimum number of characters is 6";
  }

  if (password.length > 12) {
    display.innerHTML = "maximum number of characters is 12";
  }

  switch (strength) {
    case 0:
      strengthbar.value = 0;
      break;

    case 1:
      strengthbar.value = 25;
      break;

    case 2:
      strengthbar.value = 50;
      break;

    case 3:
      strengthbar.value = 75;
      break;

    case 4:
      strengthbar.value = 100;
      break;
  }
}

password validation in javascript

/^            : Start
(?=.{8,})        : Length
(?=.*[a-zA-Z])   : Letters
(?=.*d)         : Digits
(?=.*[!#$%&?*^@"]) : Special characters
 $/              : End

 (/^
   (?=.*d)          //should contain at least one digit
  (?=.*[a-z])         //should contain at least one lower case
  (?=.*[A-Z])         //should contain at least one upper case
  [a-zA-Z0-9]{8,}  //should contain at least 8 from the mentioned characters
 $/)

Example:-   /^(?=.*d)(?=.*[a-zA-Z])[a-zA-Z0-9]{7,}$/

password validation in javascript

// Commonly used regular expression

// Check 2-9 characters, false if not matched, true if matched
const validateName = (name) => {
   const reg = /^[u4e00-u9fa5]{2,9}$/;
   return reg.test(name);
};
// Verify phone number
const validatePhoneNum = (mobile) => {
   const reg = /^1[3,4,5,6,7,8,9]d{9}$/;
   return reg.test(mobile);
};
// Check passwords consisting of 0 to 8
//uppercase and lowercase 
//alphanumeric underscores
const validatePassword = (password) => {
   const reg = /^[a-zA-Z0-9_]{0,9}$/;
   return reg.test(password);
};