Radio

Choose one of several mutually exclusive options.

Live preview
Interact with the component to see results here.
View code
HTML
<sy-radio-group
  defaultvalue="monthly"
  position="horizontal"
  size="medium"
  variant="outlined"
  name="billing"
  id="sample"
>
  <sy-radio value="monthly">Monthly</sy-radio>
  <sy-radio value="yearly">Yearly</sy-radio>
</sy-radio-group>

Usage guide

#

Let users choose exactly one mutually exclusive option. Place items inside sy-radio-group and give each a unique value.

  1. Write the error message in the error slot.

    Inside the component, add <span slot="error">Error message</span>. You can include links and other guidance as well as text. For inputs supporting noNativeValidity, enable it to show this guidance instead of a browser popup. Switch always displays errors below the component.

  2. Report business rule failures with setCustomError().

    For example, if the server rejects a duplicate value, update the error slot and call setCustomError(). This method does not take a message argument. A custom error also blocks form submission.

  3. Clear the error after resolving it and check whether submission is allowed.

    Use clearCustomError() to clear a business rule error. Required-field and format validation remain active. await checkValidity() returns true or false; reportValidity() validates and displays errors. Read valid named values through FormData on submission.

Standard option list

Use regular Radio for forms where users read descriptions before choosing.

Button selection

Show short options such as periods or view modes with sy-radio-button. Adjust group direction, size, and style together.

Examples

#

Single selection

Only one item can be selected within the same group.

View code
HTML
<sy-radio-group defaultvalue="email" name="contact">
  <sy-radio value="email">Email</sy-radio>
  <sy-radio value="sms">Text message</sy-radio>
  <sy-radio value="push">Push notification</sy-radio>
</sy-radio-group>

Button selection

Present a single-choice group as a toolbar.

View code
HTML
<sy-radio-group defaultvalue="week" variant="solid">
  <sy-radio-button value="day">Day</sy-radio-button>
  <sy-radio-button value="week">Week</sy-radio-button>
  <sy-radio-button value="month">Month</sy-radio-button>
</sy-radio-group>

Vertical layout and disabled items

Use a vertical layout for long descriptions or many options.

View code
HTML
<sy-radio-group position="vertical" defaultvalue="standard">
  <sy-radio value="standard">Standard delivery</sy-radio>
  <sy-radio value="express">Express delivery</sy-radio>
  <sy-radio value="pickup" disabled>Pickup not yet available</sy-radio>
</sy-radio-group>

Events and payloads

Interact with the component and inspect the latest event name and detail. The code includes subscriptions to events emitted by this component and its children.

View code
HTML
<sy-radio-group
  defaultvalue="monthly"
  position="horizontal"
  size="medium"
  variant="outlined"
  name="billing"
  id="sample"
>
  <sy-radio value="monthly">Monthly</sy-radio>
  <sy-radio value="yearly">Yearly</sy-radio>
</sy-radio-group>
<output id="demo-events" aria-live="polite">Interact with the component to see
  its latest event and payload.</output>

<script type="module">
  const describeResult = value => JSON.stringify(value, (_key, item) => {
    if (item instanceof File) return {
      name: item.name,
      size: item.size,
      type: item.type
    };
    if (item instanceof Element) return `<${item.localName}>`;
    return item;
  }) ?? 'Done';
  for (const name of ["changed", "selected"]) {
    document.addEventListener(name, event => {
      document.querySelector('#demo-events').textContent =
        `${event.target.localName} · ${name}: ${describeResult(event.detail)}`;
    });
  }
</script>

Solid button selection

Use filled radio buttons to show the selected yearly billing option.

View code
HTML
<sy-radio-group
  defaultvalue="yearly"
  position="horizontal"
  size="medium"
  variant="solid"
  name="billing"
  id="sample"
>
  <sy-radio-button value="monthly">Monthly</sy-radio-button>
  <sy-radio-button value="yearly">Yearly</sy-radio-button>
</sy-radio-group>

<script type="module">
  const component1 = document.querySelector("#sample");
  Object.assign(component1, {
    "variant": "solid",
    "defaultValue": "yearly"
  });
</script>

Forms and validation

Submit an empty value to trigger required-field validation. Enter a value and submit to inspect the form data, then try enabling and clearing a custom error.

View code
HTML
<form style="display:grid;gap:16px">
  <sy-radio-group
    name="field"
    required
    id="sample"
  >
    <sy-radio value="yes">Agree</sy-radio>
    <sy-radio value="no">Disagree</sy-radio><span slot="error">Select an
      option.</span>
  </sy-radio-group>
  <div style="display:flex;flex-wrap:wrap;gap:8px">
    <sy-button type="submit" variant="primary">Submit</sy-button>
    <sy-button type="reset">Reset</sy-button>
  </div>
</form>
<div class="demo-actions"
  style="display:flex;flex-wrap:wrap;gap:8px;margin-top:16px"
>
  <sy-button id="action-0" size="small">Check validity</sy-button>
  <sy-button id="action-1" size="small">Show error</sy-button>
  <sy-button id="action-2" size="small">Clear error</sy-button>
</div>
<output id="demo-result" aria-live="polite"></output>

<script type="module">
  const describeResult = value => JSON.stringify(value, (_key, item) => {
    if (item instanceof File) return {
      name: item.name,
      size: item.size,
      type: item.type
    };
    if (item instanceof Element) return `<${item.localName}>`;
    return item;
  }) ?? 'Done';
  const actionTarget0 = document.querySelector("#sample");
  document.querySelector('#action-0').addEventListener('click', async () => {
    const result = await actionTarget0.checkValidity();
    document.querySelector('#demo-result').textContent = describeResult(result);
  });
  const actionTarget1 = document.querySelector("#sample");
  document.querySelector('#action-1').addEventListener('click', async () => {
    const result = await actionTarget1.setCustomError();
    document.querySelector('#demo-result').textContent = describeResult(result);
  });
  const actionTarget2 = document.querySelector("#sample");
  document.querySelector('#action-2').addEventListener('click', async () => {
    const result = await actionTarget2.clearCustomError();
    document.querySelector('#demo-result').textContent = describeResult(result);
  });
  document.querySelector('form').addEventListener('submit', event => {
    event.preventDefault();
    document.querySelector('#demo-result').textContent = describeResult([...new FormData(event
      .currentTarget)]);
  });
</script>

Read validation results and error states

Validate before submitting or display errors on screen. Check an empty required field, then fill it to see how the return value changes. Querying the state distinguishes custom errors from required-field errors.

View code
HTML
<form style="display:grid;gap:16px">
  <sy-radio-group
    name="field"
    required
    id="sample"
  >
    <sy-radio value="yes">Agree</sy-radio>
    <sy-radio value="no">Disagree</sy-radio><span slot="error">Select an
      option.</span>
  </sy-radio-group>
  <div style="display:flex;flex-wrap:wrap;gap:8px">
    <sy-button type="submit" variant="primary">Submit</sy-button>
    <sy-button type="reset">Reset</sy-button>
  </div>
</form>
<div class="demo-actions"
  style="display:flex;flex-wrap:wrap;gap:8px;margin-top:16px"
>
  <sy-button id="action-0" size="small">Check validity</sy-button>
  <sy-button id="action-1" size="small">Show error</sy-button>
  <sy-button id="action-2" size="small">Clear error</sy-button>
  <sy-button id="action-3" size="small">Validate with errors</sy-button>
  <sy-button id="action-4" size="small">Query validation state</sy-button>
</div>
<output id="demo-result" aria-live="polite"></output>

<script type="module">
  const describeResult = value => JSON.stringify(value, (_key, item) => {
    if (item instanceof File) return {
      name: item.name,
      size: item.size,
      type: item.type
    };
    if (item instanceof Element) return `<${item.localName}>`;
    return item;
  }) ?? 'Done';
  const actionTarget0 = document.querySelector("#sample");
  document.querySelector('#action-0').addEventListener('click', async () => {
    const result = await actionTarget0.checkValidity();
    document.querySelector('#demo-result').textContent = describeResult(result);
  });
  const actionTarget1 = document.querySelector("#sample");
  document.querySelector('#action-1').addEventListener('click', async () => {
    const result = await actionTarget1.setCustomError();
    document.querySelector('#demo-result').textContent = describeResult(result);
  });
  const actionTarget2 = document.querySelector("#sample");
  document.querySelector('#action-2').addEventListener('click', async () => {
    const result = await actionTarget2.clearCustomError();
    document.querySelector('#demo-result').textContent = describeResult(result);
  });
  const actionTarget3 = document.querySelector("#sample");
  document.querySelector('#action-3').addEventListener('click', async () => {
    const result = await actionTarget3.reportValidity();
    document.querySelector('#demo-result').textContent = describeResult(result);
  });
  const actionTarget4 = document.querySelector("#sample");
  document.querySelector('#action-4').addEventListener('click', async () => {
    const result = await actionTarget4.getStatus();
    document.querySelector('#demo-result').textContent = describeResult(result);
  });
  document.querySelector('form').addEventListener('submit', event => {
    event.preventDefault();
    document.querySelector('#demo-result').textContent = describeResult([...new FormData(event
      .currentTarget)]);
  });
</script>

Custom error messages

Display a custom error for server-side duplicate checks or business rules. Change the message below and submit to verify that it is blocked. After clearing the error, required-field constraints must still be satisfied.

View code
HTML
<label for="error-message">Error message to display</label><input
  id="error-message"
  value="The server did not accept this value. Please review it."
  type="text"
>
<form style="display:grid;gap:16px">
  <sy-radio-group
    nonativevalidity
    name="field"
    required
    id="sample"
  >
    <sy-radio value="yes">Agree</sy-radio>
    <sy-radio value="no">Disagree</sy-radio><span slot="error">Select an
      option.</span>
  </sy-radio-group>
  <div style="display:flex;flex-wrap:wrap;gap:8px">
    <sy-button type="submit" variant="primary">Submit</sy-button>
    <sy-button type="reset">Reset</sy-button>
  </div>
</form>
<div class="demo-actions">
  <sy-button id="show-custom-error" variant="primary">Show error</sy-button>
  <sy-button id="clear-custom-error">Clear error</sy-button>
</div>
<output id="custom-error-result" aria-live="polite"></output>
<output id="demo-result" aria-live="polite"></output>

<script type="module">
  const describeResult = value => JSON.stringify(value, (_key, item) => {
    if (item instanceof File) return {
      name: item.name,
      size: item.size,
      type: item.type
    };
    if (item instanceof Element) return `<${item.localName}>`;
    return item;
  }) ?? 'Done';
  await (async function customErrorSetup(root) {
    const field = root.querySelector('#sample');
    const message = root.querySelector('[slot="error"]');
    const input = root.querySelector('#error-message');
    const output = root.querySelector('#custom-error-result');
    const update = async () => {
      message.textContent = input.value.trim() || _msg("m_4eea8cef81c6");
      await field.setCustomError();
      output.textContent = _msg("m_e00bd46236d3", [message.textContent]);
    };
    input.addEventListener('input', update);
    root.querySelector('#show-custom-error').addEventListener('click', update);
    root.querySelector('#clear-custom-error').addEventListener('click', async () => {
      await field.clearCustomError();
      output.textContent = await field.checkValidity() ? _msg("m_c454251167b2") : _msg(
        "m_5b8cb48627e5");
    });
    root.querySelector('form').addEventListener('invalid', () => {
      output.textContent = _msg("m_c702c7778166");
    }, true);
    root.querySelector('form').addEventListener('reset', () => {
      output.textContent = _msg("m_b90c2b4dc30f");
    });
    await update();
  })(document);
  document.querySelector('form').addEventListener('submit', event => {
    event.preventDefault();
    document.querySelector('#demo-result').textContent = describeResult([...new FormData(event
      .currentTarget)]);
  });
</script>

API reference

#

Hover over a name or focus it with the keyboard to see the code. On touch screens, tap the name.

<sy-radio-group>

Properties

Attribute / PropertyTypeDefaultDescription
booleanfalseBlock user interaction and keyboard focus.
string''Initially selected value.
booleanfalseDisplay the current value while preventing edits.
booleanfalseFail form validation when no value is provided.
'small' | 'medium' | 'large''medium'Component size.
'horizontal' | 'vertical''horizontal'Item layout direction.
'outlined' | 'solid''outlined'Component display style.
string''Field name used in FormData.
booleanfalseUse the app's error UI instead of the browser's built-in error display. checkValidity still performs validation.

Events

EventDetailDescription
CustomEvent<{ value: string; isValid: boolean; status: string }>Emitted when the value or selection state changes.

Methods

MethodReturnsDescription
Promise<boolean>Return true if the current constraints are satisfied, otherwise false.
Promise<boolean>Validate the current value and display errors to the user.
Promise<void>Set a custom error state.
Promise<void>Clear the custom error state.
Promise<"" | "custom" | "valueMissing">Return the current validation state.

Slots

SlotDescription
Component body or child items.
Validation error message.

<sy-radio>

Properties

Attribute / PropertyTypeDefaultDescription
booleanfalseSelected or on state.
booleanfalseBlock user interaction and keyboard focus.
booleanfalseDisplay the current value while preventing edits.
string''Current value or item identifier.

Events

EventDetailDescription
CustomEvent<string>Emitted when the user selects an item.

Slots

SlotDescription
Component body or child items.

<sy-radio-button>

Properties

Attribute / PropertyTypeDefaultDescription
booleanfalseSelected or on state.
booleanfalseBlock user interaction and keyboard focus.
stringundefinedCurrent value or item identifier.
'small' | 'medium' | 'large''medium'Component size.
'outlined' | 'solid''outlined'Component display style.

Events

EventDetailDescription
CustomEvent<string>Emitted when the user selects an item.

Slots

SlotDescription
Component body or child items.