From http://www.w3schools.com (Copyright Refsnes Data)

HTML 5 <legend> tag

Definition and Usage

The legend element defines a caption for the <fieldset>, <figure>, and the <details> elements.

Differences Between HTML 4.01 and HTML 5

In HTML 4.01 the <legend> tag only applied to the <fieldset> element.

In HTML 5 the <legend> tag applies to the elements: <fieldset>, <figure>, and <details>

The align attribute is no longer supported in HTML 5. Use CSS instead.

Example

Source	Output
<fieldset> <legend>Health information:</legend> Height <input type="text" size="3" /> Weight <input type="text" size="3" /> </fieldset>	Health information: Height Weight

Attributes

4: indicates if the attribute is defined in HTML 4.01
5: indicates if the attribute is defined in HTML 5

Attribute	Value	Description	4	5
align	top bottom left right	Defines the alignment for contents in the fieldset. Top is default. Not supported. Use CSS to align elements.	4

Standard Attributes

class, contenteditable, contextmenu, dir, draggable, id, irrelevant, lang, ref, registrationmark, tabindex, template, title

For a full description, go to Standard Attributes in HTML 5.

Event Attributes

onabort, onbeforeunload, onblur, onchange, onclick, oncontextmenu, ondblclick, ondrag, ondragend, ondragenter, ondragleave, ondragover, ondragstart, ondrop, onerror, onfocus, onkeydown, onkeypress, onkeyup, onload, onmessage, onmousedown, onmousemove, onmouseover, onmouseout, onmouseup, onmousewheel, onresize, onscroll, onselect, onsubmit, onunload

For a full description, go to Event Attributes in HTML 5.

Try-It-Yourself Demos

Fieldset around data
How to draw a border with a caption around your data.