Html 这个问题比较老，还有很多其他的答案，它们可能会帮助你在未来的答案中找到答案。 <table border="1"> <tr> <th>From</th>

这个问题比较老，还有很多其他的答案，它们可能会帮助你在未来的答案中找到答案。

<table border="1">
        <tr>
            <th>From</th>
            <th>Subject</th>
            <th>Date</th>
        </tr>

body {
  width: 98%;
}

table {
  width: 100%;
}


th {
  border: 1px solid black;
}


th.From, th.Date {
  width: 15%;
}

th.Date {
  width: 70%;
}


<table>
  <thead>
    <tr>
      <th class="From">From</th>
      <th class="Subject">Subject</th>
      <th class="Date">Date</th>
    </tr>
   </thead>
   <tbody>
     <tr>
       <td>Me</td>
       <td>Your question</td>
       <td>5/30/2009 2:41:40 AM UTC</td>
     </tr>
   </tbody>
</table>

<table style="border:1px; width:100%;">
    <tr>
            <th style="width:15%;">From</th>
            <th style="width:70%;">Subject</th>
            <th style="width:15%;">Date</th>
    </tr>
... rest of the table code...
</table>

table{
  table-layout:fixed;
}
th.from, th.date {
  width: 15%;
}
th.subject{
  width: 70%;
}

<table class="mytable">
    <tr>
        <th>From</th>
        <th>Subject</th>
        <th>Date</th>
    </tr>
</table>
<style>
    .mytable td, .mytable th { width:15%; }
    .mytable td + td, .mytable th + th { width:70%; }
    .mytable td + td + td, .mytable th + th + th { width:15%; }
</style>

<style>
    .mytable tr > *:nth-child(1) { width:15%; }
    .mytable tr > *:nth-child(2) { width:70%; }
    .mytable tr > *:nth-child(3) { width:15%; }
</style>

<table style="width: 100%">
    <tr>
        <th style="width: 20%">
           column 1
        </th>
        <th style="width: 40%">
           column 2
        </th>
        <th style="width: 40%">
           column 3
        </th>
    </tr>
    <tr>
        <td style="width: 20%">
           value 1
        </td>
        <td style="width: 40%">
           value 2
        </td>
        <td style="width: 40%">
           value 3
        </td>
    </tr>
</table>

<table>
    <tr>
        <th>From</th>
        <th>Subject</th>
        <th>Date</th>
    </tr>
    <tr>
        <td>Dmitriy</td>
        <td>Learning CSS</td>
        <td>7/5/2014</td>
    </tr>
</table>

table {
    border-collapse: collapse;
    width: 100%;
}

tr > * {
    border: 1px solid #000;
}

tr > th + th {
    width: 70%;
}

tr > th + th + th {
    width: 15%;
}

<table>
  <col width="130">
  <col width="80">
  <tr>
    <th>Month</th>
    <th>Savings</th>
  </tr>
  <tr>
    <td>January</td>
    <td>$100</td>
  </tr>
  <tr>
    <td>February</td>
    <td>$80</td>
  </tr>
</table>

style="column-width:300px;white-space: normal;"

<table>
    <colgroup>
       <col span="1" style="width: 30%;">
       <col span="1" style="width: 70%;">
    </colgroup>


    <tbody>
        <tr>
            <td>First column</td>
            <td>Second column</td>
        </tr>
    </tbody>
</table>