Table overflows parent div when td content is too wide

I prepared a JSFiddle to explain/show you my problem: http://jsfiddle.net/nz96C/

It looks alright at first, but when I add some text to #firsttd the whole table overflows the parent div once the tds whole width is used. I know how to solve this problem with CSS (#firstdiv {width:90px;overflow:hidden;}) but I don't know the exact number of pixels (percentage doesn't work). Also I don't want the text in the first td to wrap.

I hope you get my problem, I even have trouble explaining it in my first language.

EDIT: My goal is to have a table in which it doesn't matter how long the text in the first td is, the table should never overflow the parent div - without the text being wrapped. I want the text which overflows the first td just not to be shown.

Same answer as another very recent topic:table-layout:fixed; + width. DEMO

table {
    table-layout:fixed;
    width:100%;
}
td {
    border: 1px solid black;
    overflow:hidden;/* optionnal*/
}
#firsttd {
    white-space: nowrap;
}

edit : about comment below :

@MatthieuRiegler

table-layout:fixed; is bad if you want cell with different width.

This is your own opinion without any explanation

here is a demo where table-layout and cell's width can be different:

table {
  width: 100%;
  table-layout: fixed;
}

table,
td,
th {
  border: 1px solid;
}

thead tr th:nth-child(1) {
  width: 5em;
}

thead tr th:nth-child(2) {
  width: 20%;
}

thead tr th:nth-child(3) {
  width: 7.5em;
}

<table>
  <thead>
    <tr>
      <th>Head Cell</th>
      <th>Head Cell</th>
      <th>Head Cell</th>
      <th>Head Cell</th>
      <th>Head-Cell-Text</th>
    </tr>
  </thead>
  <tbody>
    <tr>
      <td>Cell</td>
      <td>Cell</td>
      <td>Cell</td>
      <td>Cell</td>
      <td>Cell</td>
    </tr>
    <tr>
      <td>Cell</td>
      <td>Cell</td>
      <td>Cell</td>
      <td>Cell</td>
      <td>Cell</td>
    </tr>
    <tr>
      <td>Cell</td>
      <td>Cell</td>
      <td>Cell</td>
      <td>Cell</td>
      <td>Cell</td>
    </tr>
    <tr>
      <td>Cell</td>
      <td>Cell</td>
      <td>Cell</td>
      <td>Cell</td>
      <td>Cell</td>
    </tr>
    <tr>
      <td>Cell</td>
      <td>Cell</td>
      <td>Cell</td>
      <td>Cell</td>
      <td>Cell</td>
    </tr>
  </tbody>
</table>

width + table-layout:fixed might just be a bad idea if no responsiveness is thought aside.