PHP DOM-将THEAD中的TD标记替换为TH标记

Question

我正在尝试将THEAD中的所有TD标记替换为TH标记。

我认为使用PHP DOM扩展是最好的。我对这方面还很陌生，所以我为自己缺乏知识而道歉。

我做了一些搜索，找到了如何替换标签名称。然而，我不知道如何只替换父级中的标记名（在本例中为THEAD标记）。我想把TD留在TBODY内。

以下是我的代码，用于将范围缩小到THEAD中的TD。那就是我迷路的地方。

如何将THEAD中的标签名称更改为TH？

$html = '<table>
    <thead>
        <tr>
            <td>Column 1</td>
            <td>Column 2</td>
            <td>Column 3</td>
        </tr>
    </thead>
    <tbody>
        <tr>
            <td>Column 1</td>
            <td>Column 2</td>
            <td>Column 3</td>
        </tr>
        <tr>
            <td>Column 1</td>
            <td>Column 2</td>
            <td>Column 3</td>
        </tr>
        <tr>
            <td>Column 1</td>
            <td>Column 2</td>
            <td>Column 3</td>
        </tr>
    </tbody>
</table>';
// create empty document 
$document = new DOMDocument();
// load html
$document->loadHTML(html);
// Get theads
$theads = $document->getElementsByTagName('thead');
// Loop through theads (incase there are more than one!)
for($i=0;$i<$theads->length;$i++) {
    $thead = $theads->item($i);
    // Loop through TR
    foreach ($thead->childNodes AS $tr) {
      if ($tr->nodeName == 'tr') {
          // Loop through TD
          foreach ($tr->childNodes AS $td) {
              if ($td->nodeName == 'td') {
                // Replace this tag
                }
            }
      }
    }
}

Answer 1

如果您查看了手册，可以使用以下->replaceChild()方法将td替换为th标签：

$html = '<table>
    <thead>
        <tr>
            <td>Column 1</td>
            <td>Column 2</td>
            <td>Column 3</td>
        </tr>
    </thead>
    <tbody>
        <tr>
            <td>Column 1</td>
            <td>Column 2</td>
            <td>Column 3</td>
        </tr>
        <tr>
            <td>Column 1</td>
            <td>Column 2</td>
            <td>Column 3</td>
        </tr>
        <tr>
            <td>Column 1</td>
            <td>Column 2</td>
            <td>Column 3</td>
        </tr>
    </tbody>
</table>';
// create empty document
$document = new DOMDocument();
// load html
$document->loadHTML($html);
// Get theads
$theads = $document->getElementsByTagName('thead')->item(0); // get thead tag
foreach($theads->childNodes as $tr) { // loop thead rows `tr`
    $tds = $tr->getElementsByTagName('td'); // get tds inside trs
    $i = $tds->length - 1;
    while($i > -1) {
        $td = $tds->item($i); // td
        $text = $td->nodeValue; // text node
        $th = $document->createElement('th', $text); // th element with td node value
        $td->parentNode->replaceChild($th, $td); // replace
        $i--;
    }
}
echo $document->saveHTML();

单据注释

样本输出