HTML multiple Attribute: Multiple Selections and Files

Think of filling out a sign-up page. Clear fields make the job simple; confusing fields make people leave.

What You Need to Know

Multiple changes a select from one-value choice to a control that can submit several entries under the same name.

In this example: choose several image files.

Try the Example

Take a look at the example. We’ll explain the important lines right below it.

<form action="/choose" method="post">
    <label for="subjects">Subjects (choose more than one)</label>
    <select id="subjects" name="subject" multiple size="3">
        <option value="math">Math</option>
        <option value="art">Art</option>
        <option value="music">Music</option>
    </select>
    <button type="submit">Continue</button>
</form>

Let’s Read the Code

multiple: Multiple allows several values or files where that control supports it.
<form>: The form groups controls and identifies where submitted data goes.
<label>: The label tells people what the input is for. A matching for/id pair makes the label clickable.
for: For connects a label or output with a control by ID.

Read the named elements and attributes together. They explain how the browser connects this feature to the rest of the page.

What Happens in the Browser?

The HTML controls work in the browser, but saving an answer requires the example action path to be handled by a real server.

What happens to the file? Choosing a file does not upload it immediately. The browser sends it when the form is submitted to an endpoint that accepts file uploads. The server must check the file type, size, and permissions before storing it.

Your Turn

Select two values and inspect the repeated subject keys in the request.

Common Beginner Mistakes

Copying the example without giving the fields a clear label and a usable name.
Tell users how to make multiple selections on their device; modifier keys vary by platform.

Key Takeaways

Choose the HTML feature that explains this task clearly.
multiple: Multiple allows several values or files where that control supports it.
Test the behavior you expect rather than trusting how the snippet looks in your editor.