使用带有PHP的DOM获取元素的文本但返回错误[重复]
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【中文标题】使用带有PHP的DOM获取元素的文本但返回错误[重复]【英文标题】：Get text of element using DOM with PHP but return error [duplicate] 【发布时间】：2021-03-26 01:52:04 【问题描述】：我快疯了，我不明白为什么它不起作用......
我有这个带有这个 html 的网页：
<table>
<tbody>
<tr><tr>
<tr>
<td>
<table class="style124">
<tbody>
<tr>
<td>A</td>
</tr>
<tr>
<td>B</td> //THIS !!
</tr>
</tbody>
</table>
</td>
</tr>
<tr></tr>
</tbody>
</table>
我想在<td> 中打印带有注释（“This”）的文本，我正在尝试：
$vuoto= $dom-> getElementsByClassName('style124') -> getElementsByTagName('tbody') -> getElementsByTagName('tr')[1] -> getElementsByTagName('td') ->textContent;
echo $vuoto;
但我有这个错误：
未捕获的错误：调用未定义的方法 DOMDocument::getElementsByClassName()
编辑
$url = "https://www.nihilscio.it/Manuali/Lingua%20latina/Verbi/Coniugazione_latino.asp?verbo=fero1+&lang=IT_";
$ch = curl_init($url);
curl_setopt($ch, CURLOPT_USERAGENT,'Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.17 (KHTML, like Gecko) Chrome/24.0.1312.52 Safari/537.17');
curl_setopt($ch, CURLOPT_AUTOREFERER, true);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($ch, CURLOPT_FOLLOWLOCATION, 1);
curl_setopt($ch, CURLOPT_VERBOSE, 1);
$html = curl_exec($ch);
$dom = new DOMDocument();
// set error level
$internalErrors = libxml_use_internal_errors(true);
$dom->loadHTML($html);
// Restore error level
libxml_use_internal_errors($internalErrors);
编辑 2
<body>
Il sito è in manutenzione,
<a href="../../../Posta/contatti.asp?testoerrore=fero1 /">segnalateci</a> eventuali errori.
<table>
<!-- INIZIO TABELLA PRINCIPALE-->
<tbody>
<tr>
<td style="height: 34px">
Buona navigazione con NihilScio! <a target="_blank" href="https://www.facebook.com/NihilScio/"><img src="https://www.nihilscio.it/images/fb.jpg" ></a>
</td>
</tr>
<tr>
<td class="style105">
<!--title="Herculaneum (Ercolano) - bassorilievo"-->
<br>
<span class="style112"><em>NS NihilScio</em></span>
<br><a>Educational search engine</a> <a href="../../../index.asp">Home</a>
</td>
</tr>
<tr>
<td>
<table cellspacing="0" cellpadding="0">
<tbody>
<tr>
<td>
<form name="uscita">
<table class="style123" cellspacing="0" cellpadding="0">
<tbody>
<tr>
<td style="height: 22px">
Coniugazione/declinazione
</td>
<td style="height: 22px">
</td>
</tr>
<tr title="Per favore non utilizzare caratteri accentati o speciali">
<td>
<input type="text" id="verbo" name="verbo" value="fero1 " size="60" style="font-size: 16pt; width: 200px">
<!-- <input type="submit" onclick="javascript:validainput()" value=">>" style="font-size: 14pt; width: 37px; background-color: #6699cc; color:blue; height: 25px;"/> -->
<input type="submit" onclick="speciali(' ')" value=" >> " style=" width: 40px; height: 28px; font-size:large; background-color:#99CCFF; ">
<br>
<a onclick="speciali('á')"> <span>á </span> </a>
<a onclick="speciali('é')"> <span>é </span> </a>
<a onclick="speciali('è')"> <span>è </span> </a>
<a onclick="speciali('ì')"> <span>ì </span> </a>
<a onclick="speciali('í')"> <span>í </span> </a>
<a onclick="speciali('ò')"> <span>ò</span> </a><br><br>
<a onclick="speciali('ó')"> <span>ó </span> </a>
<a onclick="speciali('ù')"> <span>ù </span> </a>
<a onclick="speciali('ú')"> <span>ú </span> </a>
<a onclick="speciali('ü')"> <span>ü </span> </a>
<a onclick="speciali('ñ')"> <span>ñ </span> </a>
<a onclick="speciali('ç')"> <span>ç</span> </a>
</td>
<td>
<a href="Coniugazione_latino.asp?verbo=fero1 &lang=EN_"> English</a>
</td>
</tr>
<tr>
<td title="Questa opzione è necessaria solo quando il vocabolo (non latino) da cercare può essere confuso con parole latine" style="height: 21px; ">
Traduci in Latino
<input type="checkbox" name="tradinv" value="1">
</td>
<td style="height: 21px">
<a href="Coniugazione_latino.asp?verbo=fero1 &lang=ES_">Español</a>
</td>
</tr>
<tr>
<td style="height: 22px; " valign="bottom"><span class="HTML_TAG">
It<input type="radio" name="lang" value="IT_" checked="checked">
En<input type="radio" name="lang" value="EN_">
Es<input type="radio" name="lang" value="ES_">
</span>
</td>
<td style="height: 22px">
<img src="https://www.nihilscio.it/Ita.png">Italiano
</td>
</tr>
</tbody>
</table>
</form>
</td>
</tr>
</tbody>
</table>
</td>
</tr>
<tr>
<td>
<!--style="height: 136px>------ SECONDA RIGA T. P. -->
<button id="frasi" onclick="javascript:PopupCentrata1('https://www.nihilscio.it/NS/EstraiFrasiClassici.asp?verbo=fero1 /&verboconsel=&lang0=IT_&lang=LT_')" class="style119"> Vocabolari e frasi</button>
<!-- <table cellspacing="0"> -->
</td>
</tr>
<tr>
<td>
<table class="style124">
<tbody>
<tr>
<td><span class="HTML_TAG">Vocaboli trovati: </span></td>
</tr>
<!--<td></td></tr> -->
<tr>
<td>
</td>
<!--<td title="">more...</td> -->
</tr>
</tbody>
</table>
</td>
</tr>
<tr><td>
<span class="style13"> fero1:</span>
<span class="HTML_ELM">vocabolo non trovato.</span><a href="../../../Posta/contatti.asp?testoerrore=fero1 /">Comunica errori</a>
</td></tr>
<tr><td>
La parola non è ancora in archivio.<br>Grazie per averla cercata<br>Riprova più tardi<br>Si raccomanda di non utilizzare segni di punteggiatura e caratteri speciali e di scrivere al massimo 5 parole interspaziate.<br>es.: puella a bonis pueris amata est <br>In caso di errore ci scusiame e la preghiamo di <a href="../../../Posta/contatti.asp?testoerrore=fero1 /">comunicarcelo.</a>
</td></tr>
<tr><td>
<a href="https://www.nihilscio.it/nihilscio.asp?cat=Latino&keyw=fero1 /" class="HTML_ELM">
<span class="style43"><strong>Continua la ricerca sul web con NihilScio</strong></span></a>
</td></tr>
<tr><td><span><em>NS-NihilScio</em>©2009-2020</span></td></tr>
</tbody></table>
<script type="text/javascript">
function Popup(apri)
var asse_x = event.clientX;
var asse_y = event.clientY;
var stile = "top="+asse_y + ",left="+asse_x + ",width=250, height=30, lacation=no, status=no, menubar=no, toolbar=no, scrollbars=no";
let newWin = window.open("", "traduzione", stile ); /*"width=200,height=200"); about:blank*/
/*newWin.document.write("Hello, world!"); */
/*let newWin = window.open("traduzione", "hello", "width=200,height=200");*/
newWin.document.write(apri);
//newWin.close();
/* window.open(apri, "", stile);*/
function PopupCentrata1(apri)
var w = 900;
var h = 350;
document.getElementById("frasi").innerHTML = '<iframe' + ' src=' + '"' + apri + '"' + ' width=' + w + ' height=' + h + '></iframe>'; //"\"" + + "\""
function visualizzatuttoatt0()
document.getElementById("ConCompAtt0").innerHTML = "";
function visualizzatuttopass0()
document.getElementById("ConCompPass0").innerHTML = "";
function visualizzatuttoatt1()
document.getElementById("ConCompAtt1").innerHTML = "";
function visualizzatuttopass1()
document.getElementById("ConCompPass1").innerHTML = "";
function visualizzatuttoatt2()
document.getElementById("ConCompAtt2").innerHTML = "";
function visualizzatuttopass2()
document.getElementById("ConCompPass2").innerHTML = "";
function visualizzatuttoatt3()
document.getElementById("ConCompAtt3").innerHTML = "";
function visualizzatuttopass3()
document.getElementById("ConCompPass3").innerHTML = "";
</script>
<script type="text/javascript">
function speciali(lettera)
document.uscita.verbo.value+= lettera;
document.uscita.verbo.focus();
;
</script>
</body>
【问题讨论】：
你在哪里见过getElementsByClassName？
【参考方案1】：
没有getElementsByClassName 函数。您可以使用https://www.php.net/manual/en/domdocument.getelementsbytagname.php 遍历特定类型的所有元素，然后检查它们的类以获取指定值https://www.php.net/manual/en/domelement.getattribute.php。或者，您可以使用xpath。
$html = '<table>
<tbody>
<tr><tr>
<tr>
<td>
<table class="style124">
<tbody>
<tr>
<td>A</td>
</tr>
<tr>
<td>B</td> //THIS !!
</tr>
</tbody>
</table>
</td>
</tr>
<tr></tr>
</tbody>
</table>';
$dom = new DOMDocument;
$dom->loadHTML($html);
$xpath = new DOMXPath($dom);
$query = '//table[contains(@class, "style124")]/tbody/tr[2]/td';
$entries = $xpath->query($query);
foreach($entries as $entry)
echo $entry->nodeValue;
https://3v4l.org/pDFhB
另外，getElementsByTagName 返回一个结果集，你不能只用-> 访问它，你需要告诉它你想要哪个。
替代方法可能是：
$html = '<table>
<tbody>
<tr><tr>
<tr>
<td>
<table class="style124">
<tbody>
<tr>
<td>A</td>
</tr>
<tr>
<td>B</td> //THIS !!
</tr>
</tbody>
</table>
</td>
</tr>
<tr></tr>
</tbody>
</table>';
$dom = new DOMDocument;
$dom->loadHTML($html);
$tables = $dom->getElementsByTagName('table');
foreach($tables as $table)
if(preg_match('/\bstyle124\b/', $table->getAttribute('class')))
$trs = $table->getElementsByTagName('tr');
$tds = $trs[1]->getElementsByTagName('td');
echo $tds[0]->nodeValue;
注意 PHP 和 xpath 之间的基本索引差异，$trs[1] 与 tr[2]。
https://3v4l.org/hLEFV
【讨论】：
我使用你的第一种方法并且有效！但是如果trim。 3v4l.org/h0H8q
nothing...not work :(此 html 在网页内，我尝试使用您的代码但没有...这是网页：nihilscio.it/Manuali/Lingua%20latina/Verbi/…
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