Return the id of the form containing the <input type="range"> element:
The result of x will be:
The form property returns a reference to the form containing the slider control.
This property returns a form object on success.
Note: This property is read only.
The form property is supported in all major browsers.
Note: The <input type="range"> element is not supported in Internet Explorer 9 and earlier versions.
|Return Value:||A reference to the form element containing the slider control. If the slider control is not in a form, null is returned|