Description:

The <fieldset> tag is used for grouping related form elements. By using the <fieldset> tag and the legend tag, you can make your forms much easier to understand for your users.

Example Code:
<form>
  <fieldset>
    <legend>Personal Information:</legend>
    Name: <input type="text" size="30" /><br />
    Email: <input type="text" size="30" /><br />
  </fieldset>
</form>
Result:
Personal Information: Name:
Email:
Attributes:
Attribute Definition
disabled Specifies that a group of related form elements should be disabled.
form Specifies one or more forms the fieldset belongs to.
name Specifies a name for the fieldset.
Global Attributes:

The <fieldset> tag also supports the Global Attributes in HTML5

Event Attributes:

The <fieldset> tag also supports the Event Attributes in HTML5