In web applications, auto populating dropdowns are commonly used to simplify user input and ensure data consistency. When a user selects a value from one dropdown, another dropdown with related data is dynamically populated.
Consider this example. Assume we have a global online store and want to allow our customers to filter products by country and city. There could be two dropdowns: one for countries and one for cities. The city dropdown will dynamically change depending on the country selected by the user, displaying only cities in that country. This feature will make it easier for users to select the correct filter, reducing confusion and providing a better user experience.
In this tutorial, I show how you can create dynamic dependent dropdown with MySQL database data using jQuery AJAX in CodeIgniter 4.