HTML 5 <thead> Tag
The HTML <thead> tag is used for adding a header to a table. 
The <thead> tag is used in conjunction with the <tbody> tag and the <tfoot> tag in determining each part of the table (header, footer, body). Browsers can use this information to enable scrolling of the table body independently of the header and footer - particuarly useful for large tables. Also, when printing a large table that spans multiple pages, this information can enable the table header and footer to be printed at the top and bottom of each page.
Note: If you use the <thead> tag, it must be used in the following context: 
- As a child of a <table>element, after any<caption>, and<colgroup>elements and before any<tbody>,<tfoot>, and<tr>elements, but only if there are no other<thead>elements that are children of the<table>element.
- The <thead>tag can contain zero or more<tr>elements and script supporting elements.
Attributes
HTML tags can contain one or more attributes. Attributes are added to a tag to provide the browser with more information about how the tag should appear or behave. Attributes consist of a name and a value separated by an equals (=) sign, with the value surrounded by double quotes. Here's an example, style="color:black;".
There are 3 kinds of attributes that you can add to your HTML tags: Element-specific, global, and event handler content attributes.
The attributes that you can add to this tag are listed below.
Element-Specific Attributes
The following table shows the attributes that are specific to this tag/element.
| Attribute | Description | 
|---|---|
| None | 
Global Attributes
The following attributes are standard across all HTML 5 tags (although the tabindex attribute does not apply to dialog elements).
- accesskey
- autocapitalize
- class
- contenteditable
- data-*
- dir
- draggable
- hidden
- id
- inputmode
- is
- itemid
- itemprop
- itemref
- itemscope
- itemtype
- lang
- part
- slot
- spellcheck
- style
- tabindex
- title
- translate
For a full explanation of these attributes, see HTML 5 global attributes.
Event Handler Content Attributes
Event handler content attributes enable you to invoke a script from within your HTML. The script is invoked when a certain "event" occurs. Each event handler content attribute deals with a different event.
- onabort
- onauxclick
- onblur
- oncancel
- oncanplay
- oncanplaythrough
- onchange
- onclick
- onclose
- oncontextmenu
- oncopy
- oncuechange
- oncut
- ondblclick
- ondrag
- ondragend
- ondragenter
- ondragexit
- ondragleave
- ondragover
- ondragstart
- ondrop
- ondurationchange
- onemptied
- onended
- onerror
- onfocus
- onformdata
- oninput
- oninvalid
- onkeydown
- onkeypress
- onkeyup
- onlanguagechange
- onload
- onloadeddata
- onloadedmetadata
- onloadstart
- onmousedown
- onmouseenter
- onmouseleave
- onmousemove
- onmouseout
- onmouseover
- onmouseup
- onpaste
- onpause
- onplay
- onplaying
- onprogress
- onratechange
- onreset
- onresize
- onscroll
- onsecuritypolicyviolation
- onseeked
- onseeking
- onselect
- onslotchange
- onstalled
- onsubmit
- onsuspend
- ontimeupdate
- ontoggle
- onvolumechange
- onwaiting
- onwheel
For a full list of event handlers, see HTML 5 event handler content attributes.
