how to check confirm password field in form without reloading page

I have a project in which I have to add a registration form and I want to to validate that the password and confirm fields are equal without clicking the register button.

If password and confirm password field will not match, then I also want to put an error message at side of confirm password field and disable registration button.

following is my html code..

<form id="form" name="form" method="post" action="registration.php"> 
    <label >username : 
<input name="username" id="username" type="text" /></label> <br>
    <label >password : 
<input name="password" id="password" type="password" /></label>     
    <label>confirm password:
<input type="password" name="confirm_password" id="confirm_password" />
    </label>
<label>
  <input type="submit" name="submit"  value="registration"  />
</label>

Is there any way to do this? Thanks in advance for any help.

Solution 1:

We will be looking at two approaches to achieve this. With and without using jQuery.

1. Using jQuery

You need to add a keyup function to both of your password and confirm password fields. The reason being that the text equality should be checked even if the password field changes. Thanks @kdjernigan for pointing that out

In this way, when you type in the field you will know if the password is same or not:

$('#password, #confirm_password').on('keyup', function () {
  if ($('#password').val() == $('#confirm_password').val()) {
    $('#message').html('Matching').css('color', 'green');
  } else 
    $('#message').html('Not Matching').css('color', 'red');
});

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<label>password :
  <input name="password" id="password" type="password" />
</label>
<br>
<label>confirm password:
  <input type="password" name="confirm_password" id="confirm_password" />
  <span id='message'></span>
</label>

and here is the fiddle: http://jsfiddle.net/aelor/F6sEv/325/

2. Without using jQuery

We will use the onkeyup event of javascript on both the fields to achieve the same effect.

var check = function() {
  if (document.getElementById('password').value ==
    document.getElementById('confirm_password').value) {
    document.getElementById('message').style.color = 'green';
    document.getElementById('message').innerHTML = 'matching';
  } else {
    document.getElementById('message').style.color = 'red';
    document.getElementById('message').innerHTML = 'not matching';
  }
}

<label>password :
  <input name="password" id="password" type="password" onkeyup='check();' />
</label>
<br>
<label>confirm password:
  <input type="password" name="confirm_password" id="confirm_password"  onkeyup='check();' /> 
  <span id='message'></span>
</label>

and here is the fiddle: http://jsfiddle.net/aelor/F6sEv/324/

Solution 2:

If you don't want use jQuery:

function check_pass() {
    if (document.getElementById('password').value ==
            document.getElementById('confirm_password').value) {
        document.getElementById('submit').disabled = false;
    } else {
        document.getElementById('submit').disabled = true;
    }
}

<input type="password" name="password" id="password" onchange='check_pass();'/>
<input type="password" name="confirm_password" id="confirm_password" onchange='check_pass();'/>
<input type="submit" name="submit"  value="registration"  id="submit" disabled/>