Here, all three columns will be center-aligned, because the col element spans three columns:

Edit code and click me	Your Result (Some examples do not work in Google Chrome):
<html> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> </head> <body> <table width="100%" border="1"> <col span="3" align="center" /> <tr> <th>ISBN</th> <th>Title</th> <th>Price</th> </tr> <tr> <td>3476896</td> <td>My first HTML</td> <td>$53</td> </tr> </table> </body> </html>
Edit the code above and click to see the result	www.xhtml.co.il - Try it yourself