Javascript Autocomplete Without External Library

When you're diving into the world of web development, one handy tool that can greatly enhance user experience is autocomplete functionality. Autocomplete helps users by suggesting possible matches as they type into a search bar or form field, making it easier and faster for them to find what they're looking for. While some developers may reach for external libraries to implement autocomplete in JavaScript, it's entirely possible to create this feature without relying on any external libraries. In this article, we'll walk you through how to implement a simple yet effective autocomplete feature using plain JavaScript.

To start off, let's look at the basic structure of what we'll be building. Our autocomplete functionality will involve an input field where users can start typing, and a list of suggestions that will dynamically update based on what the user types. We'll achieve this by using JavaScript to listen for input events in the input field and then filter a predefined list of possible suggestions based on the user's input.

The first step is to set up your HTML file with the necessary elements. You'll need an input field where users will type, and a container for the autocomplete suggestions. Here's a basic example to get you started:

<title>JavaScript Autocomplete</title>


  
  <ul id="suggestions"></ul>

Now, let's move on to the JavaScript part. Create a new JavaScript file, in this case, `autocomplete.js`, and link it to your HTML file. Within this JavaScript file, you'll need to define the list of suggestions and handle the input event to update the suggestions dynamically. Here's a simplified version of the script to give you an idea:

const suggestions = ['Apple', 'Banana', 'Orange', 'Pineapple', 'Strawberry'];
const inputField = document.getElementById('autocomplete-input');
const suggestionsList = document.getElementById('suggestions');

inputField.addEventListener('input', () => {
  const inputValue = inputField.value.toLowerCase();
  const filteredSuggestions = suggestions.filter(suggestion =>
    suggestion.toLowerCase().startsWith(inputValue)
  );

  suggestionsList.innerHTML = '';
  filteredSuggestions.forEach(suggestion => {
    const li = document.createElement('li');
    li.textContent = suggestion;
    suggestionsList.appendChild(li);
  });
});

In this script, we start by defining an array called `suggestions` that contains possible autocomplete suggestions. We then grab the input field and the suggestions container from the HTML document. Next, we add an event listener to the input field that listens for input events. When the user types something, we filter the suggestions array based on the input value and update the suggestions list accordingly.

And there you have it – a basic implementation of autocomplete without using any external libraries. You can further customize and enhance this functionality based on your project's requirements. Feel free to experiment with styling, additional features, or integrating it into a larger web application. Happy coding!