How to outline table column using JS/CSS/HTML

I need to select a table column on click. To show selection, I need to outline the table column.

I managed to outline each in the column needed, see pic: What I made

However, that doesn't suit me: I need to get rid of inner lines. CSS (actually, LESS) I currently use:

  td.fd-selected
  {
    outline: 0.25em dashed rgb(79,115,176);
    background-color: rgba(79,115,176, 0.25);
  }

Thanks!