What is the right way to size html columns?

Simple question, I was wondering, what in 2011 is the right way to size html tables? (containing tabular data, of course!)

Should the following still be the way to go?

<tr>
    <th width="45%">Name</th>
    <th width="10%">Author</th>
    <th width="20%">Description</th>
    <th width="开发者_开发百科10%">Rating</th>
    <th width="15%">Download</th>
</tr>

Or would it be better to give each column an ID (or class) and set its width with CSS?

Thank you for your input!

---

You can use col or colgroup for that purpose.

<table>
  <col class="x"/>
  <col class="y"/>
  <col class="z"/>
  <tr>
    <th>ISBN</th>
    <th>Title</th>
    <th>Price</th>
  </tr>
  <tr>
    <td>3476896</td>
    <td>My first HTML</td>
    <td>$53</td>
  </tr>
</table>

...and apply styles to the classes:

col.x {
   ...
}

---

In 2011? From about 2000 onwards it was the better approach to use class-names and CSS styles to give table-cells their width.

Unless they're all the same width, in which case just use:

th /* or td */ {
    width: 20%;
}

You could, conceivably, use nth-child too:

tr th:nth-child(1) {
    /* styles the first th of the tr */
}

JS Fiddle demo, using nth-child() css.

---

I've taken to using colgroup and col tags, like this:

<table>
    <colgroup>
        <col width="45%"></col>
        <col width="10%"></col>
        <col width="20%"></col>
        <col width="10%"></col>
        <col width="15%"></col>
    </colgroup>
    <thead>
        <tr>
            <th>Name</th>
            <th>Author</th>
            <th>Description</th>
            <th>Rating</th>
            <th>Download</th>
        </tr>
    </thead>
    <tbody>
        <tr>
            <td></td>
            <td></td>
            <td></td>
            <td></td>
            <td></td>
        </tr>
    </tbody>
</table>

---

My personal preference is to use the width attribute on column tags.

<table>
    <col width="15%"></col>
    <col width="20%"></col>
    ...etc...

It keeps the presentation part out of the table content, so to speak.