Use forms to get data from users

Learn the basics of using a form on the web with this introduction to the form element.

Imagine you want to ask people on your website about their favorite animal. As a first step, you need a way to collect the data.

In HTML, you can build this using the form element (<form>), an <input> with a <label>, and a submit <button>.

<form>
  <label for="animal">What is your favorite animal?</label>
  <input type="text" id="animal" name="animal">
  <button>Save</button>
</form>

What is a form element?

The form element consists of the start tag <form>, optional attributes defined in the start tag, and an end tag </form>.

Between the start and end tag, you can include form elements like <input> and <textarea> for different types of user input. You'll learn more about form elements in the next module.

Where is the data processed?

When a form is submitted (for example, when the user clicks the Submit button), the browser makes a request. A script can respond to that request and process the data.

By default, the request is made to the page where the form is shown.

Say you want a script running at https://web.dev to process the form data. How would you do that? Try it out on CodePen!

      <form action="https://example.com/animals"></form>

The preceding example makes a request to https://example.com/animals. A script on the example.com backend can handle requests to /animals and process data from the form.

How is the data transferred?

By default, form data is sent as a GET request, with the submitted data appended to the URL. If a user submits 'frog' in the previous example, the browser makes a request to the following URL:

https://example.com/animals?animal=frog

In this case, you can access the data on the frontend or the backend by getting the data from the URL.

If you want, you can instruct the form to use a POST request by changing the method attribute.

<form method="post">
...
</form>

Using POST, the data is included in the body of the request.

The data won't be visible in the URL and can only be accessed from a frontend or backend script.

What method should you use?

There are use cases for both methods.

For forms that process sensitive data use the POST method. The data is encrypted (if you use HTTPS) and only accessible by the backend script that processes the request. The data is not visible in the URL. A common example is a sign-in form.

If the data is shareable, you can use the GET method. Then, the data is added to your browser history, as it's included in the URL. Search forms often use this. This lets you bookmark a search result page.

Now that you've learned about the form element itself, it's time to learn about form fields to make your forms interactive.

Check your understanding

Test your knowledge of the form element

Resources

The <form> element.