Disable a group of related form elements:
The disabled attribute is supported in all major browsers, except Internet Explorer and Safari.
The disabled attribute is a boolean attribute.
When present, it specifies that a group of related form elements (a fieldset) should be disabled.
A disabled fieldset is unusable and un-clickable.
The disabled attribute is new for the <fieldset> tag in HTML5.
In XHTML, attribute minimization is forbidden, and the disabled attribute must be defined as <fieldset disabled="disabled">.
Your message has been sent to W3Schools.