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rakesh kumar
rakesh kumar

Posted on • Updated on

Explain remote validation using jquery

Dynamically check unique username and email from server side

Objective:validate input by making an asynchronous request to a server**.

<input type="text" name="username" onblur="checkUsernameAvailability(this.value)">
<script>
  function checkUsernameAvailability(username) {
    // Make an asynchronous request to check availability
  }
</script>
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The objective of remote validation with asynchronous requests is to validate input by making a request to a server to check if a particular value is available or valid. This is often used in scenarios where you want to verify the uniqueness of a username, email, or any other input without reloading the entire page.

Here's an example of remote validation using asynchronous requests for checking the availability of a username:

<input type="text" name="username" onblur="checkUsernameAvailability(this.value)">
<div id="usernameAvailabilityMessage"></div>

<!-- JavaScript -->
<script src="https://code.jquery.com/jquery-3.6.4.min.js"></script>
<script>
  function checkUsernameAvailability(username) {
    // Make an asynchronous request to check availability
    $.ajax({
      url: '/check-username-availability', // Replace with your server-side endpoint
      method: 'POST',
      data: { username: username },
      success: function(response) {
        // Handle the response from the server
        if (response.available) {
          $('#usernameAvailabilityMessage').text('Username is available');
        } else {
          $('#usernameAvailabilityMessage').text('Username is not available');
        }
      },
      error: function() {
        // Handle the error if the request fails
        $('#usernameAvailabilityMessage').text('Error checking username availability');
      }
    });
  }
</script>
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In this example:

HTML Input Field:

<input type="text" name="username" onblur="checkUsernameAvailability(this.value)">
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The onblur event is triggered when the user leaves the username input field. It calls the checkUsernameAvailability function with the current value of the input.

JavaScript Function:

function checkUsernameAvailability(username) {
  // Make an asynchronous request to check availability
  $.ajax({
    url: '/check-username-availability', // Replace with your server-side endpoint
    method: 'POST',
    data: { username: username },
    success: function(response) {
      // Handle the response from the server
      if (response.available) {
        $('#usernameAvailabilityMessage').text('Username is available');
      } else {
        $('#usernameAvailabilityMessage').text('Username is not available');
      }
    },
    error: function() {
      // Handle the error if the request fails
      $('#usernameAvailabilityMessage').text('Error checking username availability');
    }
  });
}
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  1. The function uses jQuery's $.ajax to make an asynchronous request to the server.
  2. The url parameter should be replaced with the actual server-side endpoint that handles the username availability check.
  3. The data parameter sends the username to the server.
  4. The success callback handles the server's response. In this case, it updates a message div (#usernameAvailabilityMessage) to inform the user whether the username is available or not.
  5. The error callback handles any errors that may occur during the request . Note: Make sure to replace the server-side endpoint ('/check-username-availability') with the actual endpoint on your server that performs the username availability check. The server should respond with a JSON object indicating whether the username is available or not. Let's explore a couple more examples of remote validation using asynchronous requests. We'll focus on scenarios like checking email availability and validating a password against certain criteria.

Checking Email Availability:

<!-- HTML -->
<input type="email" name="email" onblur="checkEmailAvailability(this.value)">
<div id="emailAvailabilityMessage"></div>

<!-- JavaScript -->
<script src="https://code.jquery.com/jquery-3.6.4.min.js"></script>
<script>
  function checkEmailAvailability(email) {
    // Make an asynchronous request to check email availability
    $.ajax({
      url: '/check-email-availability', // Replace with your server-side endpoint
      method: 'POST',
      data: { email: email },
      success: function(response) {
        // Handle the response from the server
        if (response.available) {
          $('#emailAvailabilityMessage').text('Email is available');
        } else {
          $('#emailAvailabilityMessage').text('Email is not available');
        }
      },
      error: function() {
        // Handle the error if the request fails
        $('#emailAvailabilityMessage').text('Error checking email availability');
      }
    });
  }
</script>
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This example is similar to the username availability check, but it checks the availability of an email address.

Password Strength Validation:

<input type="password" name="password" oninput="checkPasswordStrength(this.value)">
<div id="passwordStrengthMessage"></div>

<!-- JavaScript -->
<script src="https://code.jquery.com/jquery-3.6.4.min.js"></script>
<script>
  function checkPasswordStrength(password) {
    // Make an asynchronous request to check password strength
    $.ajax({
      url: '/check-password-strength', // Replace with your server-side endpoint
      method: 'POST',
      data: { password: password },
      success: function(response) {
        // Handle the response from the server
        $('#passwordStrengthMessage').text(response.message);
      },
      error: function() {
        // Handle the error if the request fails
        $('#passwordStrengthMessage').text('Error checking password strength');
      }
    });
  }
</script>
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In this example, the script checks the strength of a password against certain criteria, such as length, uppercase letters, lowercase letters, and digits.

Remember to replace the server-side endpoints ('/check-email-availability' and '/check-password-strength') with the actual endpoints on your server that perform the necessary checks. The server should respond with a JSON object indicating the result of the validation.

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