colspan is an attribute of the td tag. It allows a table cell to span some columns. See table 1
table 1 cell1 cell2 cell3 cell4 with colspan=2 cell5
You can also use rowspan (see table 1).
table 2 cell1 with rowspan=2 cell2 cell3 cell4 cell5
Or combine both (see table 3)
table 3 cell1 with rowspan=2 and colspan=2 cell2 cell3 cell4 cell5 cell6
cellpadding controls the distance between a cell's border and the content. For the first table I set it to 0, for the second to 20.
cellspacing controls the distance between borders. (table 4 uses 0, table 5 uses 20)
table 4 cell1 cell2 cell3 with colspan=2
table 5 cell1 cell2 cell3 with colspan=2
To control column width you can either set width within the td tag or insert a colgroup tag:
You can use span in the col tag to get columns of the same width as in
<col span=3 width=500>
gives you a table with one column of 200pixels and 3 of 500 pixels width.