How to hide columns in HTML table?

You need to use Style Sheet for this purpose.

<td style="display:none;">

You can use the nth-child CSS selector to hide a whole column:

#myTable tr > *:nth-child(2) {
    display: none;
}

This works under assumption that a cell of column N (be it a th or td) is always the Nth child element of its row.

Here's a demo.

​ If you want the column number to be dynamic, you could do that using querySelectorAll or any framework presenting similar functionality, like jQuery here:

$('#myTable tr > *:nth-child(2)').hide();

Demo with jQuery

(The jQuery solution also works on legacy browsers that don't support nth-child).

you can also use:

<td style="visibility:hidden;">
or
<td style="visibility:collapse;">

The difference between them that "hidden" hides the cell but it holds the space but with "collapse" the space is not held like display:none. This is significant when hidding a whole column or row.