Those tags helps you to keep organized the content of your table according to the rows. You're supposed to put the
<thead> around the first row
(<tr>) of your table. Then you should type the last row of the table with the
<tfoot> tag around. If you put the
<tbody> before the
<tfoot> it wont work. So at last all the content' rows of your table should be inside the
<tbody> tags.
These are additional tags, so the difference if you dont use them is the order in which you write your table
Using the thead, tfoot and tbody:
<table>
<thead><tr><td>title1</td><td>title2</td><td>title3</td></tr></thead>
<tfoot><tr><td>last1</td><td>last2</td><td>last3</td></tr></tfoot>
<tbody>
<tr><td>row1</td><td>row1</td><td>row1</td></tr>
<tr><td>row2</td><td>row2</td><td>row2</td></tr>
<tr><td>row3</td><td>row3</td><td>row3</td></tr>
<tr><td>row4</td><td>row4</td><td>row4</td></tr>
</tbody>
</table>
Not using them:
<table>
<tr><td>title1</td><td>title2</td><td>title3</td></tr>
<tr><td>row1</td><td>row1</td><td>row1</td></tr>
<tr><td>row2</td><td>row2</td><td>row2</td></tr>
<tr><td>row3</td><td>row3</td><td>row3</td></tr>
<tr><td>row4</td><td>row4</td><td>row4</td></tr>
<tr><td>last1</td><td>last2</td><td>last3</td></tr>
</table>