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

HTML 5 <nest> tag

Definition and Usage

The <nest> tag defines a nestingpoint in a datatemplate for child elements. Used together with the elements <datatemplate> and <rule>.

Differences Between HTML 4.01 and HTML 5

The <nest> tag is new in HTML 5

Tips and Notes

Tip: The child nodes to be inserted, must match the <nest> element's <rule> element.

Attributes

Attribute	Value	Description
filter	selector	Defines which of the child nodes that can processed further
mode	mode	Defines which mode the datatemplate's rules will have

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.