Password Validation

 

Password Validation Form

<div class="container">
  <form action="/action_page.php">
    <label for="usrname">Username</label>
    <input type="text" id="usrname" name="usrname" required>
    <label for="psw">Password</label>
  <  input type="password" id="psw" name="psw" pattern="(?=.*\d)(?=.*[a-z])(?=.*[A-Z]).{8,}" title="Must contain at least one number and one uppercase and lowercase letter, and at least 8 or more characters" required>
    <input type="submit" value="Submit">
  </form>
</div>
<div id="message">
  <h3>Password must contain the following:</h3>
  <p id="letter" class="invalid">A <b>lowercase</b> letter</p>
  <p id="capital" class="invalid">A <b>capital (uppercase)</b> letter</p>
  <p id="number" class="invalid">A <b>number</b></p>
  <p id="length" class="invalid">Minimum <b>8 characters</b></p>
</div>

Note: We use the pattern attribute (with a regular expression) inside the password field to set a restriction for submitting the form: it must contain 8 or more characters that are of at least one number, and one uppercase and lowercase letter.

 

Style the input fields and the message box:

/* Style all input fields */
input {
    width: 100%;
    padding: 12px;
    border: 1px solid #ccc;
    border-radius: 4px;
    box-sizing: border-box;
    margin-top: 6px;
    margin-bottom: 16px;
}
/* Style the submit button */
input[type=submit] {
    background-color: #4CAF50;
    color: white;
}
/* Style the container for inputs */
.container {
    background-color: #f1f1f1;
    padding: 20px;
}
/* The message box is shown when the user clicks on the password field */
#message {
    display:none;
    background: #f1f1f1;
    color: #000;
    position: relative;
    padding: 20px;
    margin-top: 10px;
}
#message p {
    padding: 10px 35px;
    font-size: 18px;
}
/* Add a green text color and a checkmark when the requirements are right */
.valid {
    color: green;
}
.valid:before {
    position: relative;
    left: -35px;
    content: "✔";
}
/* Add a red text color and an "x" icon when the requirements are wrong */
.invalid {
    color: red;
}
.invalid:before {
    position: relative;
    left: -35px;
    content: "✖";
}

 

<script>
var myInput = document.getElementById("psw");
var letter = document.getElementById("letter");
var capital = document.getElementById("capital");
var number = document.getElementById("number");
var length = document.getElementById("length");
// When the user clicks on the password field, show the message box
myInput.onfocus = function() {
  document.getElementById("message").style.display = "block";
}
// When the user clicks outside of the password field, hide the message box
myInput.onblur = function() {
  document.getElementById("message").style.display = "none";
}
// When the user starts to type something inside the password field
myInput.onkeyup = function() {
  // Validate lowercase letters
  var lowerCaseLetters = /[a-z]/g;
  if(myInput.value.match(lowerCaseLetters)) {
    letter.classList.remove("invalid");
    letter.classList.add("valid");
  } else {
    letter.classList.remove("valid");
    letter.classList.add("invalid");
}
  // Validate capital letters
  var upperCaseLetters = /[A-Z]/g;
  if(myInput.value.match(upperCaseLetters)) {
    capital.classList.remove("invalid");
    capital.classList.add("valid");
  } else {
    capital.classList.remove("valid");
    capital.classList.add("invalid");
  }
  // Validate numbers
  var numbers = /[0-9]/g;
  if(myInput.value.match(numbers)) {
    number.classList.remove("invalid");
    number.classList.add("valid");
  } else {
    number.classList.remove("valid");
    number.classList.add("invalid");
  }
  // Validate length
  if(myInput.value.length >= 8) {
    length.classList.remove("invalid");
    length.classList.add("valid");
  } else {
    length.classList.remove("valid");
    length.classList.add("invalid");
  }
</script>