input type=radio element | input type=radio object

[This documentation is preliminary and is subject to change.]

Creates a radio button control.

Standards information

• HTML 4.01 Specification, Section 17.4

HTML information

DOM Information

Inheritance Hierarchy

Remarks

Use a radio button control to limit a user's selection to a single value within a set of values. To do this, you must link together each button in a set of radio buttons by assigning each button the same name.

When a user submits a form, a selected radio button generates a name/value pair in the form data only if the button has a value.

To select a radio button as the default button in a set, set the checked property of the button to true.

A user can select a radio button only if the button has a name. To clear a selected radio button, a user must select another button in the set.

Windows Internet Explorer 8 and later. In IE8 Standards mode, you can select an input type=radio button that does not have a name attribute specified. In addition, dynamically setting the name attribute on an input type=radio button correctly applies that button to the same named group. For more information, see Defining Document Compatibility.

Touching on the label associated with a radio button has the same effect as touching the radio button directly.

Examples

This example uses the <label> tag to include the text with the checkbox to increase the touch sensitive area of the checkbox.

<label><input id="red" type="checkbox" name="colors" value="red" />Text</label>

This example uses the INPUT type=radio element to create three radio buttons.

<INPUT type=radio name="radio" CHECKED>1-10 years old
<INPUT type=radio name="radio">11 years old
<INPUT type=radio name="radio">12-120 years old

This example uses script to detect which radio button the user selects.

<SCRIPT>
function detect()
{
    if (radio[0].checked)
        alert("You're between 1 and 10 years old.")
    else if (radio[1].checked)
        alert("You're 11 years old.")
    else
        alert("You're between 12 and 120 years old.")
}
</SCRIPT>

See also

input

Reference

input

Conceptual

Introduction to Forms

Build date: 3/8/2012