table-layout:auto;
thead 1 thead 2 thead 3
th 1 td 1 td 2 td 3
th 2 td 5 td 6 td 7
th 3 td 9 td 10 td 11

table-layout:fixed;
thead 1 thead 2 thead 3
th 1 td 1 td 2 td 3
th 2 td 5 td 6 td 7
th 3 td 9 td 10 td 11