底部边框未显示（表格）

Question

<body>
  <table>
    <table style="width:70%; margin:0 auto;">
        <tr style="margin:0; border-bottom: 2px solid black; padding:0;">
          <td colspan="2"><img src="pre_header.jpg" alt="" style="width: 100%"></td>
        </tr>
        <tr style="margin:0; padding:0;">
          <td style="width:35%; margin-left:0;"><img style="width: 100%" src="logo.jpg" alt=""></td>
          <td style="width:35%; clear:right; margin-right: 0;"><h1 style="margin-left: 2rem">Monday 16<sup>th</sup> december 2019 <br> Volume 5</h1></td>
        </tr>
        <tr style="border-bottom: 4px solid #000;">
          <th style="text-align: center;" colspan="2"><h1>SEBI Updates</h1></th>
        </tr>

为什么这里没有显示底部边框？picture of what is happening

Answer 1

添加到 table 样式 border-collapse:collapse;

<body>
  <table>
    <table style="width:70%; margin:0 auto;border-collapse:collapse;">
        <tr style="margin:0; border-bottom: 2px solid black; padding:0;">
          <td colspan="2"><img src="pre_header.jpg" alt="" style="width: 100%"></td>
        </tr>
        <tr style="margin:0; padding:0;">
          <td style="width:35%; margin-left:0;"><img style="width: 100%" src="logo.jpg" alt=""></td>
          <td style="width:35%; clear:right; margin-right: 0;"><h1 style="margin-left: 2rem">Monday 16<sup>th</sup> december 2019 <br> Volume 5</h1></td>
        </tr>
        <tr style="border-bottom: 4px solid #000;">
          <th style="text-align: center;" colspan="2"><h1>SEBI Updates</h1></th>
        </tr></table></table>

底部边框未显示（表格）

Bottom Border not showing up (tables)

html

css

html-table

border