Disabling Browser Autocomplete on Web Form Fields

Disabling browser autocomplete on web form fields is a common requirement for many web applications, especially those that handle sensitive information such as passwords or credit card numbers. In this tutorial, we will explore the various methods to disable browser autocomplete and provide examples of how to implement them.

Understanding Browser Autocomplete

Browser autocomplete is a feature that allows browsers to automatically fill in form fields with previously entered data. While this feature can be convenient for users, it can also pose security risks if sensitive information is stored in the browser’s cache.

Using the autocomplete Attribute

The most straightforward way to disable browser autocomplete is by using the autocomplete attribute on the form field. This attribute can be set to off to prevent the browser from autocompleting the field.

<input type="text" name="foo" autocomplete="off">

However, it’s worth noting that some browsers, such as Firefox and Chrome, may ignore this attribute for password fields.

Randomizing Form Field Names

Another approach is to randomize the form field names by adding a session-specific string to the end of the name. This makes it difficult for the browser to find context for the field and can help prevent autocomplete.

<input type="text" name="<?php echo 'foo_' . session_id(); ?>">

Using autocomplete="new-password"

For password fields, you can use the autocomplete="new-password" attribute to indicate that the field is for a new password. This can help prevent browsers from autocompleting the field with previously entered passwords.

<input type="password" name="pass" autocomplete="new-password">

Fixing Browser Autofill Issues

In some cases, even with autocomplete="off", browsers may still autofill fields with incorrect data. To fix this issue, you can use a workaround that involves setting the field to readonly and removing the attribute on focus.

<input type="password" readonly onfocus="this.removeAttribute('readonly');" onblur="this.setAttribute('readonly', true);">

This approach can help prevent browsers from autofilling fields with incorrect data.

Best Practices

When disabling browser autocomplete, it’s essential to consider the following best practices:

• Use the autocomplete attribute sparingly and only when necessary.
• Randomize form field names to prevent browsers from finding context for the field.
• Use autocomplete="new-password" for password fields to indicate that the field is for a new password.
• Test your implementation thoroughly to ensure that it works as expected in different browsers.

By following these best practices and using the methods outlined in this tutorial, you can effectively disable browser autocomplete on web form fields and improve the security of your web application.