Definition and Usage
The <thead> tag is used to group the header content in an HTML table.
The thead element should be used in conjunction with the tbody and tfoot elements.
The tbody element is used to group the body content in an HTML table and the tfoot element is used to group the footer content in an HTML table.
Note: <tfoot> must appear before <tbody> within a table, so that a browser can render the foot before receiving all the rows of data.
Notice that these elements will not affect the layout of the table by default. However, you can use CSS to let these elements affect the table's layout.