Python handler:

@liveview_handler("submit_contact")
def submit_contact(consumer, content):
    from .forms import ContactForm

    form = ContactForm(content["form"])

    if form.is_valid():
        # Save to database
        contact = form.save()

        # Show success message
        html = render_to_string("contact_success.html", {
            "message": "Thank you! We'll be in touch."
        })
    else:
        # Show form with errors
        html = render_to_string("contact_form.html", {
            "form": form
        })

    send(consumer, {
        "target": "#contact-container",
        "html": html
    })

HTML template:

<div id="contact-container">
    <form>
        <input type="text" name="name" placeholder="Name" required>
        <input type="email" name="email" placeholder="Email" required>
        <textarea name="message" placeholder="Message" required></textarea>

        <button
            data-liveview-function="submit_contact"
            data-action="click->page#run"
            type="button">
            Submit
        </button>
    </form>
</div>

@liveview_handler("validate_field")
def validate_field(consumer, content):
    field_name = content["data"]["field"]
    field_value = content["form"].get(field_name, "")

    # Validate
    error = None
    if field_name == "email" and "@" not in field_value:
        error = "Invalid email address"
    elif field_name == "name" and len(field_value) < 3:
        error = "Name must be at least 3 characters"

    # Show error or success
    html = f'<span class="{"error" if error else "success"}">{error or "✓"}</span>'

    send(consumer, {
        "target": f"#error-{field_name}",
        "html": html
    })

<input
    type="text"
    name="email"
    data-liveview-function="validate_field"
    data-data-field="email"
    data-action="blur->page#run">
<span id="error-email"></span>