Use collapse value for visibility property of the col tag you need. E.g. for hiding column c2 use:
#c2 {
visibility: collapse;
}
And also to zero out the width of the collapsed column, set the col element's width to 0 while setting the table element's table-layout css property to fixed value:
#c2 {
visibility: collapse;
width:0;
}
and
<table style="table-layout:fixed;...">
...